CLASS ASTEROPSIDA – Diversity of Life

CLASS ASTEROPSIDA (Brongniart 1843)

EUKARYA> ARCHAEPLASTIDA> VIRIDIPLANTAE> STREPTOBIONTA> EMBRYOPHYTA> TRACHEOPHYTA> SPERMOPHYTA> ANGIOSPERMOPHYTA> ASTEROPSIDA

ANGIOSPERMOPHYTA LINKS

Phylum Angiospermophyta

Class Nymphaeopsida

Class Magnoliopsida

Class Liliopsida

Class Ceratophyllopsida

Asteropsida (as-tur-OP-si-da) is derived from the genus Aster, the Latin word for star, and one of the most important genera in the sunflower family. The suffix is derived from the Greek for that which resembles (opsis -οψισ). Together, they mean that which resembles an Aster.

INTRODUCTION TO THE ASTEROPSIDA

The Asteropsida, includes a bewildering array of flowering plants and range in form from large woody trees to small spring ephemerals. Nearly 70% of all species in the flowering plants and six of the 10 most speciose families occur in this group. Figure 1 illustrates that the asteropsids (or the eudicots) are monophyletic but many uncertainties remain. APG III (2009) gives a more complete picture of the uncertainties, particularly among the basal groups. This group is also called the tricolpates, a term that refers to the synapomorphy of tricolpate pollen. Other characters are more variable, but generally the flowers are in cyclic whorls of four or five segments. Otherwise, they possess a suite of primitive characters: net-veined leaves, eustelic stems, and dicotyledonous embryos.

The structure of the core Asteropsida (=Eudicots or Tricolpates) generally has two major monophyletic clades called the Rosids, and the Asterids (see Figure 1). At the base is a collection of unresolved taxa (a collective that I call the Basal Tricolpates). Even between the three resolved clades, the branching order is not identified. So, although many question marks remain in this colossal taxon, much is known. In general, the following descriptions of taxa come from Judd et al. (2002), and Judd and Olmstead (2004). The following text describes the major orders and families of the Asteropsida. Click on the highlighted ordinal and family names to see the context of the group within the more complete taxonomic system of APG II (2003), APG III (2009), and Judd et al. (2002).

BASAL TRICOLPATES. This collection of paraphyletic taxa has the primitive characters of many floral segments and seeds with copious endosperm. Figure 2 illustrates the relationship of the basal tricolpates (in green) to the rest of the eudicots.

RANNUNCULALES is defined well by molecular analyses; however, morphological synapomorphies are problematic. Plants in this order contain distinctive alkaloids, particularly the alkaloid berberine. They tend to be herbaceous with toothed, lobed, or even-compound leaves. Their flowers are hypogynous (text with tooltip) with floral parts distinct and free. The seeds (text with tooltip) are tiny with copious endosperm (text with tooltip) . The families of this order are sisters to the rest of the eudicots (Judd and Olmstead 2004, Soltis et al. 2004).

RANNUNCULACEAE

The buttercup family is a mostly herbaceous group within the Rannunculales, a basal order of the eudicots. The family is almost cosmopolitan, especially the weedy species. The natural range of the family is the temperate and boreal parts of the northern hemisphere. The buttercups have only 47 genera but 2000 species, 400 of which are in Ranunculus (Figure 3). Many species have been domesticated and bred as ornamentals. They include the garden buttercups as well as Anemone, Delphinium, and Clematis.

The leaves are usually alternate and sometimes a basal rosette. The blades may be simple or compound, and usually there are stipules (text with tooltip) at the leaf base, though they may be quite inconspicuous. The flowers are variable but most are similar to Figure 4. They are hypogynous and usually have distinct sepals (text with tooltip) and petals (text with tooltip) . The stamens (text with tooltip) are numerous but have distinct filaments. The pistils are numerous and separate with a short style and an elongate stigma. The fruits (text with tooltip) are variable, but usually follicles (text with tooltip) , achenes (text with tooltip) , or berries (text with tooltip) .

PAPAVERACEAE

The poppies make up the basal family within the Rannunculales. They are herbs or shrubs that have simple vessels (text with tooltip) and a milky latex (text with tooltip) . Globally, they occur in the northern temperate zone with some in southern Africa and Australia. The family has 40 genera and 770 species. Most are weedy plants (e.g. Chelidonium). Many are grown as ornamentals [prickly poppy (Argemone), California poppy (Eschscholzia), poppy (Papaver), bloodroot (Sanguinaria), and bleeding heart (Dicentra)]. However, the latex of Papaver somniferum (Figure 5) yields opium, and its seeds are used as a flavoring.

The leaves are alternate or in a basal rosette (text with tooltip) . Usually the leaves are compound or highly dissected and have no stipules. The typically large and showy flowers (text with tooltip) are perfect (text with tooltip) , and hypogynous. Most are actinomorphic, but the group that includes bleeding heart is decidedly zygomorphic (Figure 6). They have many stamens that have filaments. The fruits usually are capsules (text with tooltip) . Poppies like Papaver have a particular capsule which opens by pores along the top.

CORE EUDICOTS Most of the tricolpate flowering plants occur in this clade which has two relatively large monophyletic groups within it: Rosids, and Asterids. Floral parts usually are in fives (pentamerous), and there is a strong differentiation between the sepals and petals (Judd and Olmstead 2004). APG II (2003) and APG III (2009) have a few unresolved orders among the basal Core Eudicots; however, Gunnerales consistently emerges as the sister to the rest of the Core Eudicots (APG II 2003, APG III 2009, Soltis et al. 2003, Hilu et al. 2003).

ROSID CLADE This is a very large group of orders which consists of a collection of unresolved basal orders and two well-defined clades of Core Rosids: Eurosids I (Fabids) and Eurosids II (Malvids). This collection of orders includes the Vitales (the order that includes Vitaceae, the Grape Family), which may be the sister group to all other Rosids (Judd and Olmstead 2004). Within the Eurosids, there are two major clades: Eurosids I or Fabids and Eurosids II or Malvids.

ORDER VITALES

VITACEAE

These plants usually are lianas. Tendrils and inflorescences are opposite leaves. The flowers are small with variable number of reduced corolla segments (4-5 sepals and petals). The number of stamens equals the number of petals. The ovulary is hypogynous, and the fruit is a berry. The most important members of the family are grapes, especially Vitis vinifera (Figure 8). The berries of these fruits contain large concentrations of sugar and tannins. Typically, mature fruits of grapes have a bloom formed by yeasts, particularly Saccharomyces. Humanity discovered quite early that the food of the grape could be conserved by allowing the juice to undergo alcoholic fermentation thus stabilizing and preserving it. The same yeasts also were used in making leavened bread.

EUROSIDS I (THE FABIDS) This clade emerged in the molecular analyses of APG I (1998), APG II (2003), and APG III (2009) as Eurosids I, and later it was given the name Fabids by Judd and Olmstead (2004) and APG III (2009). The Fabids tend to have the following characters: apocarpous monomerous (or pseudomonomerous) gynoecium, and hypogynous flowers. Many taxa have a nodule-forming symbiosis with microorganisms in which nitrogen-fixation occurs.

ORDER MALPIGHIALES Although molecular analyses indicate a strong monophyletic relationship among the members of this order, clear morphological synapomorphies are lacking. Characters that occur in many but not all of the families are: dry stigmas (text with tooltip) , fibrous exotegmen, and trilacunar nodes. This order has 35 families and 13,100 species.

EUPHORBIACEAE

The Spurge family is the 7th largest family of flowering plants with 320 genera and 6100 species. The genus Euphorbia alone has around 2000 species. Euphorbs occur throughout the tropics and extend into the temperate regions of the northern and southern hemispheres. Economically important species include ornamentals like poinsettia (Euphorbia, Figure 9), and croton (Codiaeum). The source of natural rubber (Hevea brasiliensis, Figure 10), tung oil (Aleurites), and other vegetable waxes occur in this family. Many plants are poisonous, including Ricinus (Figure 11), the castor bean plant, which is the source of the infamous ricin (as well as castor oil by which I was sure that I was being poisoned when I was a boy).

The plants are woody and often with latex. Generally, the leaves are simple and may or may not have stipules. The flowers are hypogynous and imperfect (text with tooltip) , usually with a reduced perianth (text with tooltip) . Carpels are fused with as many styles (text with tooltip) as carpels. Many plants (e.g. poinsettia) produce a bisexual inflorescences that are subtended by colorful bracts (Figure 12). The fruit usually is a capsular schizocarp (text with tooltip) . The seeds have oily endosperm.

VIOLACEAE

The violets make up a small family that occurs throughout temperate regions. There are 22 genera and 950 species, of which Viola (Figure 13) has about 500 species. Some Viola species are used as ornamentals, but mostly plants like Johnny Jump-Ups are weeds. Violet flowers are well adapted for insect pollination with a landing platform, a nectary, and lines on the lip of the zygomorphic flower that serve as guides to the insect. Short-tongued bees, like bumble bees, short-circuit the floral structure and often chew directly into the spur or nectary on the back. During the summer violets produce cleistogamous flowers, flowers that do not open and are self-pollinating. So, they outcross through the spring and self during the summer through which time they can make hundreds of seeds.

The family has plants that are trees, shrubs or herbs. Most of the familiar taxa are herbs that grow as rosettes. However, the plants may have upright stems with alternate, opposite, spiral, or two-ranked (text with tooltip) leaves. Usually the leaves are simple and may be with or without stipules. The flowers have a perianth of 5 sepals and 5 petals. The flowers are perfect and zygomorphic (text with tooltip) . Stamens are usually 5 in a ring around the gynoecium (text with tooltip) , which is formed from 3 fused pistils. The fruit is a loculicidal (text with tooltip) capsule (Figure 14).

SALICACEAE

The willow family ranges from the tropics throughout the northern hemisphere. The plants generally are associated with water. The Salicaceae has 58 genera and 1210 species, of which Salix is the dominant genus with 450 species. The willows and poplars are used for ornamental plantings as well as for lumber and wood pulp.

The family is made of fast-growing trees and shrubs. The leaves are alternate, simple, and stipulate. The flowers are very reduced (no corolla (text with tooltip) and a reduced calyx (text with tooltip) ), imperfect, and borne in unisexual catkins (text with tooltip) (Figure 15). The seeds are tiny and dispersed by means of seed hairs. The mature seed has no endosperm.

ORDER FABALES The monophyly of the order is well-supported by molecular analyses. Morphological synapomorphies include: vessel elements with single perforations, a large, green embryo, and the presence of ellagic acid. This order has 4 families and 18,860 species.

FABACEAE

The Fabaceae is the bean family, a diverse group of plants with 630 genera and 19,400 species, the third largest family of flowering plants. The diversity in vegetative and floral form separates the Fabaceae into three subfamilies, which are all united on the basis of the fruit, the legume. Indeed, the old Linnaean name for the family is Leguminosae. The legumes (text with tooltip) are global in distribution and have very many economically important species including peanuts (Arachis), chickpeas (Cicer), soybeans (Glycine), lentils (Lens), and pea (Pisum, Figures 16 and 17). Some are grown to be grazed on and for silage, for example: alfalfa (Medicago), sweet clover (Meliotus), clover (Trifolium), and vetch (Vicia). Almost all of the economically important plants are in the Faboideae (see below), the herbaceous legumes with zygomorphic flowers. Many legumes enter into symbiotic relationships with nitrogen-fixing soil bacteria mostly in the genus, Rhizobium. The bacteria enter the roots and induce the formation of a nodule. Thus, many legumes, particularly the economically important taxa, are rich in plant proteins.

Overall, legumes are plants with alternate, pinnately compound, and stipulate leaves. Flowers mostly occur in racemes (text with tooltip) , corymbs (text with tooltip) , spikes (text with tooltip) or heads (text with tooltip) . They vary from actinomorphic to strongly zygomorphic with 5 sepals and 5 petals. The gynoecium is a single carpel which produces a dry and dehiscent legume. The embryo is large, and the mature seed has no endosperm.

Further descriptions of the subfamilies can be found below:

Faboideae (also called Papilionoideae): These are the herbaceous legumes with showy zygomorphic flowers. The leaves are pinnately compound to trifoliate (a reduced pinnate condition). This is the most diverse and most economically important family and does seem to be monophyletic.

Mimosoideae: These are woody plants with actinomorphic flowers. They are trees to shrubs with leaves having fern-like double compound leaves. The inflorescence is made of many inconspicuous actinomorphic flowers that have elongate and showy stamens. This group, likely monophyletic, includes Mimosa (Figure 18), and Acacia (Figure 19).

Cesalpineoideae: These are trees and shrubs with zygomorphic flowers. The leaves are simple or pinnately compound. The flower has a showy corolla. Dominant taxa include Cassia, Cercis (Figure 20), Gleditsia, and Senna. This group appears to be polyphyletic with the Mimosoideae emerging from within it (Judd et al. 2002 and 2008).

ORDER ROSALES The monophyly of this group is well-supported by molecular analyses. Despite its morphological variability, the order may be defined by the following synapomorphies: lack of endosperm, the presence of a hypanthium which was lost in those with highly reduced flowers. This order has 11 families and 6,300 species.

ROSACEAE

The rose family is very diverse and cosmopolitan in its distribution. The family has 85 genera and 3000 species. It is a basal group in the Rosales and a sister group to the clade of all other Rosales families (Judd et al. 2008). The character that seems to set it apart from the other Rosales families is numerous stamens. The family has many plants that produce economically important edible fruits such as the: apple (Malus); almond, apricot, cherry, peach, and plum (Prunus); pear (Pyrus), raspberry, blackberry (Rubus); strawberry (Fragaria); quince (Cydonia); loquat (Eriobotrya). The family also includes many ornamentals such as crab apples, flowering cherries, hawthorn, spiraea, mountain ash, and roses.

Taxa of the Rosaceae vary from large woody trees to small herbaceous plants. The leaves are variable; alternate or opposite; simple or compound; and with or without stipules. The perianth is usually showy with 5 sepals and 5 petals. Stamens are numerous. The gynoecium is quite variable; apocarpous (text with tooltip) or syncarpous (text with tooltip) . Thus, the fruit is variable. Formerly, the subfamilies were defined on the basis of the kind of fruit. Takhtajan (1997) had as many as 12 subfamilies, but most systems (e.g. Schulze-Menz 1964 and Judd et al. 2002) had 5 or 4, respectively. Potter et al. (2007) in a study of 88 taxa using of six nuclear genes and four chloroplast regions, found only three subfamilies: Rosoideae, Spiraeoideae, and Dryadoideae.

Further descriptions of the subfamilies with illustrations can be seen below:

Rosoideae: The flower of Fragaria (strawberry, Figure 21) is typical of this subfamily. Note the swollen, cone-shaped receptacle in the center of the flower on which sit numerous separate pistils. In general, rosoids produce a fruit that has a swollen receptacle, which may form either an aggregate of drupelets or achenes. If the receptacle encloses the drupelets, it forms a hip (Figure 22). Note the separate pistils surrounded by the floral tube. If the achenes/drupelets are on the outside of the receptacle, it forms aggregates like strawberry and raspberry.

Spiraeoideae (sensu lato): This taxon has been expanded by the coalescence of three traditional subfamilies: classical Spiraeoideae (sensu stricto), “Maloideae”, and “Prunoideae” or “Amygdaloideae” (Potter et al. (2007).
- Classical Spiraeoideae: Plants have dry fruits, which usually are capsules. The illustrated plant has inflorescences that are terminal and broad (Figure 23) together with capsules that have dehisced.
- “Maloideae”: The fruit is formed from an epigynous flower that has 5 fused pistils. This fruit is fleshy and is called a pome. Note the photograph (Figure 24) that shows the longitudinal section of a Malus, Apple, fruit.
- “Prunoideae or Amygdaloideae”: Flowers have a hypanthium which has a single pistil (and a pair of ovules). The fleshy fruit that develops has a stony inner ovulary wall, which becomes the pit in the fruit called a drupe. See a photograph of the drupe of Prunus persica, Peach, in longitudinal section (Figure 25).

Dryadoideae: Formerly, the few members of this taxon have been associated with the Rosoideae. Potter et al. (2007) show, however, that they are a separate lineage that shares some biochemical characters with the Spiraeoideae, but, in addition, have root nodules that house nitrogen-fixing bacteria in the genus Frankia (Eubacteria>Firmicutae>Actinobacteria). The fruits are achenes or aggregates of achenes. Figure 26 shows Dryas, a small alpine plant that has flowers like Fragaria, but they have 8 petals.

MORACEAE

The mulberry or fig family is widely distributed from tropical to temperate areas. The family has 53 genera and 1500 speceis, 800 of which are in the genus Ficus. Edible fruits are figs (Ficus, Figure 27), mulberries (Morus), and breadfruit (Artocarpus, Figure 28). Ornamentals species come from Ficus, Maclura, and Dorstenia. Ficus is one of the most important genera in the tropics, particularly in the rainforests. The plant provides many niches for epiphytes and insects, which in turn support many different vertebrates.

The fruits of taxa in the Moraceae are multiple, which may be formed by unisexual or bisexual inflorescences. Ficus has such a bisexual inflorescence called a synconium, a fruit type in which the receptacle almost completely encases the inflorescence of staminate and pistilate flowers (see Figure 27). The opening at the top allows the pollinator, usually a wasp, to enter and lay its eggs. The movements of the adult allow for pollination. The developing grubs of the solitary wasps feed on the fleshy receptacles that are formed after fertilization. Larger animals feed on the synconia, too, and disperse the seeds.

Members of the Moraceae are trees, shrubs, vines or herbs with lactifers in all their parenchymatous tissue. Leaves (text with tooltip) usually are alternate, 2-ranked or spiral, and usually simple and stipulate. The flowers are unisexual (imperfect). The have 4-5 tepals and staminate flowers have an equal number of stamens. The ovulary (text with tooltip) may be epigynous (text with tooltip) or hypogynous, but it has only a single locule. The fruits are variable but usually they are achenes, drupes (text with tooltip) or nuts (text with tooltip) as part of a multiple fruit (text with tooltip) .

ORDER CUCURBITALES The members of this order share the characters of epigynous and imperfect flowers, parietal placentation (text with tooltip) , cucurbitoid tooth type, cucurbitacins (oxidized triterpenes), and separate vascular bundles (text with tooltip) in the stem. This order has three families with four more possibly indicated by molecular analyses.

CUCURBITACEAE

The Cucumber family is mainly a family of tropical and subtropical species with 118 genera and 825 species. Economically important plants include pumpkin, squashes, and gourds (Cucurbita); cantaloupe, muskmelon, honeydew melon, and cucumber (Cucumis); watermelon (Citrullus); and Luffa (as vegetable sponges).

Members of this family generally are vines with tendrils that coil and arise from the nodes (Figure 29). The leaves do not have stipules. Generally the flowers are unisexual with the plants being monoecious or dioecious. Floral petals are fused at the base and usually into a bell-like cone. The flowers are epigynous and the fruit that they produce is a particular type of berry in which the outer floral layer (from the epigynous flower) develops a hard outer rind, a fruit type called a pepo (text with tooltip) .

ORDER FAGALES The morphological synapomorphies for this order are: imperfect flowers with tepals (text with tooltip) reduced or missing; usually epigynous. Staminate flowers in catkins; plants wind-pollinated. Fruits indehiscent with one seed (usually a nut).

FAGACEAE

The oak family includes trees and shrubs that occur throughout the northern hemisphere. Its diversity is modest with only 9 genera but 900 species, 450 of which are in the genus Quercus (the oaks). Economically important plants include edible chestnuts (Castanea). Mostly they are prized for their wood for furniture and cabinetry. White oak was and remains the wood of choice for barrels because it imparts little flavor to its contents (or much flavor when the barrel is charred inside and used to age distilled spirits). Many oaks, beeches, and chestnuts are grown as ornamentals.

Leaves of this family are, alternate, simple, pinnately veined, and most are awned, particularly the oaks, have lobed leaves. The flowers are small and imperfect. Often the staminate flowers are in catkins (Figure 30). Pistillate flowers are subtended by an involucre (text with tooltip) of many bracts (text with tooltip) . The fruit usually is a nut, but can be a samara (text with tooltip) or drupe. The mature seed has no endosperm.

JUGLANDACEAE

The walnut family is widespread but has only 8 genera and 59 species. Edible nuts come from walnut (Juglans); and hickory and pecan (Carya). Most of the walnuts are prized hardwoods for furniture and cabinetry. Hickory is used for tool handles and smoking meat. Often the trees are grown as ornamentals.

Walnuts inhibit the germination and growth of plants around them by the release of allelopathic compounds, particularly juglone. In addition, the stems of Juglans are distinctive because of their chambered pith (Figure 31).

Members of this family are aromatic trees or shrubs. The leaves are alternate and pinnately compound. The flowers are imperfect with 4 tepals. Staminate flowers have 3 to many stamens and occur in catkins. The pistilate flowers are solitary, epigynous, and have a gynoecium of 2 united carpels. The fruit is often a drupe-like nut. The embryo of the mature seed has little or no endosperm, and it is oily.

EUROSIDS II (THE MALVIDS) This is a monophyletic clade (see Figure 32) according to APG I (1998) , APG II (2003), and APG III (2009). Although it has eight orders, the malvids comprise a relatively small group with the Brassicales, Malvales, and the Sapindales among the dominant orders. Despite its size and strong support, unifying morphological characters have not emerged. Judd and Olmstead (2004) define the clade from a molecular perspective and describe the ordinal components.

ORDER BRASSICALES (CAPPARALES) Synapomorphies for this small but diverse order are the presence of glucosinolates and myrosin cells. When glucosinolates and myrosinase (in the myrosin cells) come together, mustard oils are released. This order has 15 families.

BRASSICACEAE

The mustard or caper family is found throughout the world with a relatively high diversity (419 genera and 4,130 species). Many economically important plants are in this family including radishes (Raphanus); capers (Capparis); cabbage, kale, broccoli, cauliflower, Brussels sprouts, kohlrabi, turnip, and black mustard (Brassica); white mustard (Sinapsis); horseradish (Amoracia). Vegetable oils come from Brassica (B. napus). Ornamentals include cleome, rocket, wallflower, money plant, sweet alyssum, and rock cress. Many weeds occur in this family including Arabidopsis thaliana, the main plant used for molecular plant studies.

Usually the mustards are weedy herbs but can be trees or shrubs. The leaves are alternate and often in basal rosettes (Figure 33). The forms of the leaves vary from simple to compound to dissected and may or may not have stipules. The flowers are usually in terminal racemes. Perianth segments are distinct and in 4’s (Figure 34). The petals form a distinctive cross pattern and thus the old Linnaean name for them was Cruciferae (the cross bearers). Usually, the stamens are 6 with four long and two short. Note that the four long stamens above the plane formed by the petals in Figure 33. The fruit usually is a special capsule called a silique (Figure 35).

ORDER MALVALES Synapomorphies for this order include stratified phloem (text with tooltip) (layers of fibrous and soft phloem), wedge-shaped rays, mucilage canals (text with tooltip) , stellate hairs, connate sepals, and malvoid leaf teeth. About 9 families and 3,560 species.

MALVACEAE

The mallow family occurs throughout the world with 243 genera and 4225 species. It is the 9th largest flowering plant family. Several very important products of mallow plants include chocolate (Theobroma, Figure 36), cola (Cola), and okra (Hibiscus). The family also contains plants that produce balsa wood (Ochroma); basswood or linden (Tilia); kapok (Ceiba & Bombax); and cotton (Gossypium). Some of the major ornamental plants from the Malvaceae are: basswood/linden (Tilia), flannelbush (Fremontodendron), hollyhock (Althaea), and hibiscus and tree of Sharon (Hibiscus).

Mallows are variable in form and can be trees, herbs or shrubs. This diversity is reflected in the organization of the family which has 9 subfamilies. Look to the descriptions below of the plants with free stamens (a large paraphyletic group), and a monophyletic group of taxa with fused stamens.

Plants with free stamens: Examples of these plants include Jute (Chorchorus, Figure 37) and Linden or Basswood (Tilia). The leaves are alternate and palmately veined with stipules. The flowers are hypogynous and perfect. The stamen filaments (text with tooltip) are many and free. The gynoecium usually of variable fused pistils (text with tooltip) . Fruit is a capsule.

Plants with stamens fused in a tube around the style: Examples of these plants include Hibiscus (Figure 38). The leaves are alternate and palmately veined with stipules. The flowers are hypogynous and perfect. The stamen filaments are fused into a distinctive tube around the style. The gynoecium is formed from 5 fused pistils, each with a separate stigma. The fruit is capsular.

ORDER SAPINDALES Synapomorphies for this order include pinnately compound leaves, flowers with a distinctive nectar disk. They are woody with alternate, spiral leaves. Flowers small and 4-5 merous with imbricate perianth segments. The order has 9 families and 5,800 species.

SAPINDACEAE

The soapberry family includes the maples and horse chestnuts. They occur primarily in the tropics but genera like Acer are important elements of the northern temperate forests. The family, as it is now defined, has 147 genera and 2,215 species. Some members of this family produce edible fruits (e.g. lychee), and vegetable soap (from Sapindus); some Acer species yield maple sugar. By far, though, the product of this family is wood and ornamentals. The wood, particularly of maple, is highly prized as a furniture and cabinet wood.

Molecular and morphological work (Gadek et al. 1996, Judd et al. 1994, Soltis et al. 2000) has confirmed the monophyly of the soapberries, the maples, and the horse chestnuts, all formerly separated into the families: Sapindaceae, Aceraceae, and Hippocastanaceae, respectively. According to Judd et al. (2002) the family as now constituted has three nested clades: the hippocastanoid clade (the horse chestnuts and relatives), the samaroid clade (the maples and relatives), and the sapindoid clade (the soapberries).

Plants in the soapberry or maple family are trees, shrubs or vines. The leaves may be opposite or alternate and spiral, pinnately compound or simple with palmate venation (Figure 39). Flowers are hypogynous, perfect or imperfect, and actinomorphic (text with tooltip) (sometimes zygomorphic). The calyx of 4-5 sepals, corolla of 0 or 4-5 petals. Stamens variable 4-10, free; gynoecium of 2-3 united carpels, and 2 styles; fruit a schizocarp that can be drupe-like or winged to become a samara.

RUTACEAE

The citrus or rue family occurs mainly in the tropics, and it has 155 genera and 930 species. Citrus (Figure 40) is an important genus that provides the fruits: oranges, tangerines, grapefruits, limes, and lemons. Many taxa provide medicinal plants and ornamentals.

Plants in the citrus family are trees with aromatic oil glands. The leaves are distinctive with winged petioles. Otherwise, they may be alternate or opposite, simple or compound, and without stipules. The flowers are perfect, hypogynous, actinomorphic, and most often in cymes. The calyx has 4-5 segments that may be free or united. The corolla may have 0, or 4-5 mostly free, petals. They usually have 8-10 stamens, but they are numerous in some taxa. The gynoecium is a compound pistil. The fruit may be a capsule, hesperidium (text with tooltip) , drupe, or samara.

CARYOPHYLLID CLADE Within the Core Asterids, the Caryophylliid Clade emerges as a monophyletic order of 33 families. It is a sister to the Core Asterids (APG III 2009). Other orders that form the paraphylletic Caryophylliid Group are Berberidopsidiales and Santalales (see Figure 41).

ORDER CARYOPHYLLALES Clear molecular and morphological synapomorphies define this order. Their phloem has sieve tubes (text with tooltip) that contain plastids, a peripheral ring of proteinaceous filaments, and a central protein crystal. Betalains form red-yellow pigments. The flower has a single whorl of tepals, and the embryo is curved within the seed. This order has 33 families and more than 11,000 species.

CACTACEAE

The cactus family includes herbs, shrubs, or trees. Cacti are found almost exclusively in the Americas, although the natural range of a few species includes Africa. Mainly, cacti are plants of deserts and arid environments; however, some taxa have evolved to be epiphytes in rainforests (even in rainforests, epiphytes occupy very local arid environments). The family is somewhat diverse with 93 genera and 1400 species. Many species are grown as ornamentals. Some species of Opuntia (Figure 42) yield edible fruits called prickly pears. Peyote cactus (Lophophora) contains mescaline.

Most cacti are succulent with leaves that are opposite, alternate or whorled, and usually reduced to a spine. The stems, which usually are the photosynthetic organs, have simple vessels. The flowers are usually perfect with numerous stamens (usually 2X as many as there are perianth segments). The tepals are numerous and showy (Figure 43). The flower is epigynous such that the fruit (usually a berry) often develops with spiny stem tissue on the outside. The seed is variable, but it has a large, curved embryo, which is a character of the clade.

ASTERID CLADE The asterids have been recognized for many years (e.g. Olmstead et al. 1992) as a monophyletic group. Judd and Olmstead (2004) give the following as possible synapomorphies for the clade:

Ovules are unitegmatic (a single integument).

The nucellus is thin and megaspore mother cell develops just beneath the epidermis, a process called tenuinucellate.

The occurrence of Iridoids, a kind of monoterpene and an intermediate in the formation of alkaloids.

Most have flowers that are sympetalous. Cronquist (1988) referred to these taxa as the Sympetalae.

Stamens tend to be epipetalous (they are attached to the petals at least at the base).

The gynoecium tends to be of two or three fused carpels.

BASAL ASTERIDS Taxa in this paraphyletic group (Figure 43) often have more stamens than petals.

ORDER ERICALES Though molecular support for monophyly of this group is strong, there are no clear morphological synapomorphies with the exception of theoid leaf teeth (a vein enters the tooth and ends in a gland). As defined by Judd et al. (2002) this order has 24 families and 9,450 species.

ERICACEAE

The heath family is made up of shrubs and small trees that are cosmopolitan, and grow mainly in well-lit, acid habitats. The family has 130 genera and 2700 species, of which Rhododendron has around 800 species. Economically important plants are blueberries and cranberries (Vaccinium, Figure 45); and ornamentals including Rhododendron, Erica, Kalmia, Calluna, Pieris, and Oxydendrum. The Ericaceae as constituted here also includes Pyrolaceae, Monotropaceae, Empetraceae, and Epacridaceae of older systems (e.g. Gleason 1981).

The leaves most often are are alternate and spiral, but some are opposite or whorled. The leaves are small, firm, perennial, and lack stipules. The flowers are perfect and most often in racemes. Perianth segments are in 5’s and the stamens are 5-10 (e.g. Kalmia, Figure 46). The gynoecium is made of 2-10 fused pistils, and it may be epigynous or hypogynous. The fruit is usually capsular, but when fleshy the fruit is a drupe or a berry.

EUASTERIDS I (THE LAMIID CLADE) The Lamids (named in Judd and Olmstead 2004, Figure 48) have flowers that begin development with separate corolla primordia, but fuse later (Endress 2001).

ORDER SOLANALES Morphological synapomorphies may include actinomorphic flowers with a plicate, sympetalous corolla. They tend to have alternate, simple leaves and flowers in which the number of stamens equals the number of petals. The order has 6 families and 7400 species.

SOLANACEAE

The potato or nightshade family is global in distribution, but most diverse in the new world tropics. It has 147 genera and 2,930 species, most of which (1400) are in the genus Solanum. Edible plants include tomatoes (Figure 47), eggplants, and potatoes (Solanum); peppers (Capsicum); and tomatillos (Physalis). Most members of this family are poisonous, including most of the plants that have edible products. The poisons are usually alkaloids, some of which are narcotic. These include tobacco (Nicotiana, Figure 49), belladona (Atropa), and jimsonweed (Datura). Solanaceae also provides many ornamental plants (e.g. nightshade, groundcherry, angel’s trumpet).

The solanaceous plants are mostly herbaceous, but they can be shrubs or vines. The leaves are alternate but vary from simple to compound, and they have no stipules. The flowers are perfect, actinomorphic, and 5-merous with the 5 stamens attached to the corolla tube. The gynoecium most often has 2 carpels. The fruit is a capsule or a berry. Endosperm may or may not be present.

ORDER GENTIALES This is a monophyletic order with the synapomorphies of stipules (sometimes very reduced), glandular hairs (colleters) on the undersides of leaves. The order has 5 families and 14,200 species.

RUBIACEAE

The Rubiaceae is the most speciose family in the Gentiales. It is the 4th largest flowering plant family with 550 genera and 13,183 species. The family is global in distribution and contains several economically important plants. Chief among them is coffee (from the seed of Coffea, Figure 50); quinine (from the bark of Cinchona); and epicac (Psychotria). The important ornamentals include Gardenia (Figure 51), Hamelia, Pentas, Hedyotis.

Rubiaceae is sister to all of the other families in the Gentiales. It is differentiated from them by having epigynous flowers and stipules that are interpetiolar, between the petioles of opposite leaves. This family has plants that can be trees, shrubs, vines, or herbs, typically with alkaloids and raphide crystals. The leaves are mostly opposite, but sometimes they are whorled. The leaf margins are entire, pinnately veined, and stipulate. They have distinctive pubescent leaves and petals. The flowers are perfect and actinomorphic. The perianth is made up of 4-5 sepals and an equal number of petals that are pubescent and fused at the base making a bell-shaped corolla. The androecium is of 4-5 sepals with their filaments fused to the petals. The gynoecium is formed by 2 fused pistils (sometimes 5) and epigynous. The fruit is variable: capsule, berry, drupe, schizocarp, or indehiscent pod.

ORDER LAMIALES The mophological synapomorphies for this order include: gland-headed hairs, oligosaccharides (no starch); parenchyma extending from anther connective into the locule of the anther (text with tooltip) ; embryos of the onograd type; endosperm with large micropylar haustorium; and protein inclusions into the nuclei of mesophyll cells. The order has 24 families and 17,800 species.

LAMIACEAE

The mint family is global in its distribution and quite diverse with 258 genera and 7,173 species. It is the sixth largest plant family. Taxa in this family provide many essential oils and spices such as peppermint and spearmint (Mentha, Figure 52); lavender (Lavandula); horehound (Marrubium); catnip (Nepeta); basil (Ocimum); oregano (Origanum); rosemary (Rosmarius); sage (Salvia); savory (Satureja); thyme (Thymus). Teak wood (from Tectona, Figure 53) and many ornamentals also come from this family.

The mints are mainly herbs, but some grow as shrubs or trees. Stems are square in the herbaceous taxa. Leaves are opposite, simple, and without stipules. The flowers are perfect with a 5-merous perianth. The corolla is fused and strongly zygomorphic. The orchid-like flowers of the mints prompted Linnaeus to name the family Labiatae, the lip flowers. The flowers have 5 stamens and a gynoecium of 2 carpels, each with 2 ovules. The fruit is formed by the carpels separate into four 1-seeded nutlets. Endosperm is usually lacking in the mature seed.

EUASTERIDS II (THE CAMPANULIDS) The Campanulids (named by Judd et al. 2004, Figure 54) have fused petal primordia early in development (Erbar 1991, and Erbar and Leins 1996).

ORDER APIALES The synapomorphies of these families include: distinctive resin-oil canals associated with the vascular tissue, characteristic arrangement of lateral roots, a tiny embryo, reduced leaves at the base of the shoots. This order has 2 families and 4250 species.

APIACEAE

The carrot family is global in its distribution and is comprised of 460 genera and 4250 species. Many plants provide food and flavorings. Among them are dill (Anethum); celery (Apium); caraway (Carum); coriander (Coriandrum); cumin (Cuminum); carrot (Daucus, Figure 55); fennel (Foeniculum); parsnip (Pastinacea); parsley (Petroselenium); anise (Pimpinella); ginseng (Panax). Despite the large number of edible species, many are deadly poisonous. Water hemlock (Conium), the juice of which Socrates used to commit suicide, is in this family. Some plants are ornamentals [e.g. English ivy (Hedera, Figure 56) and Shefflera].

Plants of this family mostly are herbaceous, but a few are woody. The leaves are alternate and compound or dissected. The petiole is broad and sheathing (very obvious in celery). The flowers are small, usually perfect, and occur in umbels (text with tooltip) (see Figure 55) or compound umbels. For this reason, Linnaeus named the family Umbelliferae, the umbel bearers. Overall, the flowers are 5-merous. The gynoecium is formed of 2-5 fused carpels and epigynous. There are as many styles as many as carpels. Fruit is a drupe, berry or schizocarp. The seeds small with abundant endosperm.

ORDER ASTERALES Morphological synapomorphies for this order include: photosynthate stored in the form of the oligosaccharide inulin; ellagic acid; plunger pollination (stamens surround the style in a tube; special hairs on the style help to remove the pollen and then the style elongates to present pollen (text with tooltip) clusters to a floral visitor). This order has 12 families and 24,900 species.

ASTERACEAE

The sunflower family is global in its distribution and remarkably diverse with 1,535 genera and with 23,600 species, it is the largest plant family (almost as many species as there are bony fish). Many edible plants are found in this family including endive and chicory (Cichorium, Figure 57); artichoke (Cynara); sunflower seeds and Jerusalem artichokes (Helianthus; Figure 58); and lettuce (Lactuca). Some are noxious weeds [e.g. ragweed (Ambrosia) and dandilion (Taraxacum, Figure 59)], and some are ornamentals [e.g. marigold (Calendula); chrysanthemum (Leucantheum); sunflower (Helianthus); Zinia].

Mostly the plants of this family are herbs, and many are weedy requiring disturbance to flourish. The main storage product of the Asteraceae is a polysaccharide called inulin rather than starch, and some plants have latex. Leaves are usually alternate, simple, and without stipules. The inflorescence (text with tooltip) is a head (see Figure 60a) or a set of compound heads. This inflorescence, which was once called a composite is the source of the Linnaean name, Compositae. Flowers are epigynous, sympetalous, and usually perfect. Some of the flowers are neutral or functionally staminate. Ray flowers are zygomorphic (Figure 60b), and disk flowers are actinomorphic and 5-merous (Figure 60c). The five stamens are fused around the style. The whole inflorescence is often subtended by many scaly bracts called an involucre. The fruit is an achene, often with a persistent pappus (text with tooltip) at the top (see Figure 59).

Calyceraceae, the sister family to the Asteraceae persists in Australia, New Zealand, New Guinea, and New Caledonia. Members of this family resemble the composites in many ways including the occurrence of a head and an achene-like fruit. Other related families have a similar geographic distribution.

The Asteraceae has a complex evolutionary history that seems to have spanned almost all of the continents except Antarctica, and the diversity of the Asteraceae is reflected in the biogeography of the subfamilial taxa. The basal subfamilies are in South America and appear to be remnants of the earliest radiation (see Figure 61). Barreda et al. (2010) report the occurrence of fossil pollen from these basal groups throughout the southern continents (Australia, Africa, and South America) and suggest that they emerged from a general southern continental distribution after the isolation of Antarctica. Thus, centers of evolution in Africa are consistent with such a southern continental distribution followed by successful radiation into the northern continents.

Funk et al. (2009a&b), who seem to prefer the name Compositae, report 12 subfamilies and 43 tribes within the Asteraceae. Members of the Barnadesioideae (e.g. Chuquiraga, Figure 62) are the sisters to the rest of the family. They were first recognized as such by Jansen and Palmer (1987 and 1988) who discovered that only this subfamily did not have a particular chloroplast DNA inversion that is universal to the rest of the family. Also, they do not have latex, their stamens are not fused, and the involucral bracts usually are spine-tipped.

The more modern types of composites produce heads of three major types: disk flowers only, ligulate flowers only, and complex heads with both disk and ligulate flowers. Thistles (e.g. Cirsium, Carduoideae; Figure 63) have a head of disk flowers subtended by a globose involucre. Dandilion (Taraxacum, Cicoroideae; Figure 59) has heads of ligulate flowers. Aster (Figure 64), like other members of the Asteroideae has heads of both disk and ligulate flowers.

LITERATURE CITED

APG I, K. Bremer, M. W. Chase, P. F. Stevens, A. A. Anderberg, A. Backlund, B. Bremer, B. G. Briggs, P. K. Endress, M. F. Fay, P. Goldblatt, M. H. G. Gustafsson, S. B. Hoot, W. S. Judd, M. Kallersjo, E. A. Kellogg, K. A. Kron, D. H. Les, C. A. Morton, D. L. Nickrent, R. G. Olmstead, R. A. Price, C. J. Quinn, J. E. Rodman, P. J. Rudall, V. Savolainen, D. E. Soltis, P. S. Soltis, K. J. Sytsma, and M. Thulin (Angiosperm Phylogeny Group). 1998. An Ordinal Classification for the Families of Flowering Plants. Annals of the Missouri Botanical Garden. 85:531-553.

APG II, B. Bremer, K. Bremer, M. W. Chase, J. L. Reveal, D. E. Soltis, P. S. Soltis, P. F. Stevens, A. A. Anderberg, M. F. Fay, P. Goldblatt, W. S. Judd, M. Källersjö, J. Kårehed, K. A. Kron, J. Lundberg, D. L. Nickrent, R. G. Olmstead, B. Oxelmann, J. C. Pires, J. R. Rodman, P. J. Rudall, V. Savolainen, K. J. Sytsma, M. van der Bank, K. Wurdack, J Q.-Y. Xiang, and S. Zmartzy. 2003. The update of the angiosperm phylogeny group classification for the orders and families of flowering plants: APG II. Botanical Journal of the Linnean Society. 141:399-436.

APG III, B. Bremer, K. Bremer, M. W. Chase, M. F. Fay, J. L. Reveal, D. E. Soltis, P. S. Soltis, P. F. Stevens, A. A. Anderberg, M. J. Moore, R. G. Olmstead, P. J. Rudall, K. J. Sytsma, D. C. Tank, K. Wurdack, J Q.-Y. Xiang, and S. Zmartzy. 2009. An update of the angiosperm phylogeny group classification for the orders and families of flowering plants: APG III. Botanical Journal of the Linnean Society. 161: 105-121.

Barkman, T. J., G. Chenery, J. R. McNeal, J. Lyons-Weiler, W. J. Ellisens, G. Moore, A. D. Wolfe, and C. W. dePamphilis. 2000. Independent and combined analyses of sequences from all three genomic compartments converge on the root of flowering plant phylogeny. Proceedings of the National Academy of Sciences U.S.A. 97:13166-13171.

Barreda, V., L. Palazzesi, M. C. Telleria, L. Katinas, J. V. Crisci. 2010. Review of Paleobiology and Palynology. 160: 102-110.

Bowe, L. M., G. Coat, and C. W. dePamphilis. 2000. Phylogeny of seed plants based on all three genomic compartments: Extant gymnosperms are monophyletic and Gnetales’ closest relatives are conifers. Proceedings of the National Academy of Sciences (USA) 97:4092-4097.

Cameron, K. M., M. W. Chase, W. M. Whitten, P. J. Kores, D. C. Jarrell, V. A. Albert, T. Yukawa, H. G. Hills, and D. H. Goldman. 1999. A phylogenetic analysis of the Orchidaceae: Evidence from RBCL nucleotide sequences. American Journal of Botany. 86(2): 208-224.

Chase, M., D. E Soltis, R. G. Olmstead, D. Morgan, D. H. Les, B. D. Mishler, M. R. Duvall, R. Price, H.G Hillis, Y. Qui, K. A. Kron, J.H. Rettig, E. Conti, J. D. Palmer, J. R. Manhart, K. J. Sytsma, H. J. Michaels, W. J. Kress, K. G. Karol, W. D. Clark, M. Hedren, B. S. Gaut, R. K. Jansen, K. Kim, C. F. Wimpee, J. F. Smith, G. R. Furnier, S. H. Strauss, Q. Xiang, G. M. Plunkett, P. S. Soltis, S. M. Swensen, S. E. Williams, P. A. Gadek, C. J. Quinn, L. E. Eguiarte, E. Golenberg, G. H. Learn, Jr., S. Graham, S. C. H. Barrett, S. Dayanandan, and V. A. Albert. 1993. Phylogenetics of seed plants: An analysis of nucleotide sequences from the plastid gene rbcL. Ann. Missouri Bot. Gard. 80: 528-580.

Chaw S.-M., C. L. Parkinson, Y. Cheng, T. M. Vincent, and J. D. Palmer. 2000. Seed plant phylogeny inferred from all three plant genomes: Monophyly of extant gymnosperms and origin of Gnetales from Conifers. Proceedings of the National Academy of Sciences USA) 97:4086-4086.

Cronquist, A. 1981. An Integrated System of Classification of Flowering Plants. New York. Columbia Univ. Press. New York.

Dahlgren, R. M. T. and H. T. Clifford. 1982. The Monocotyledons – A Comparative Study. Academic Press, New York.

Darwin, C. R. originally published 1862. On the Various Contrivances by which British and Foreign Orchids are Fertilised by Insects, and on the Good Effects of Intercrossing. John Murray. London.
Davies, T. J., T. G. Barraclough, M. W. Chase, P. S. Soltis, D. E. Soltis, and V. Savolainen. 2004. Darwin’s abominable mystery: insights from a supertree of the angiosperms. Proceedings of The National Academy of Sciences 101: 1904-1909.

Donoghue, M. J. and J. A. Doyle. 2000. Seed plant phylogeny: demise of the anthophyte hypothesis? Current Biology 10:R106-R109. [C]

Doyle, J. A. 2006. Seed ferns and the origin of angiosperms. Journal of the Torrey Botanical Society. 133(1): 169-209.

Endress, P. K. and J. A. Doyle. 2009. Reconstructing the ancestral angiosperms flower and its initial specializations. American Journal of Botany. 96(1): 22-66.

Field, T. S. and N. C. Arens. 2007. The ecophysiology of early angiosperms. Plant Cell and Environment. 30: 291-309.

Freudenstein, J. V., C. van den Berg, D. H. Goldman, P. Kores, M. Molvray, and M. W. Chase. 2004. An expanded plastid DNA phylogeny of Orchidaceae and analysis of Jackknife branch support strategy. American Journal of Botany. 91(1): 149-157.

Friis, E. M. and P. Crane. 2007. New home for tiny aquatics. Nature. 446: 269-270.

Frohlich, M. W. and M. W. Chase. 2007. After a dozen years of progress the origin of angiosperms is still a great mystery. Nature. 450: 1184-1189.

Funk, V. A., A. Susanna, T. F. Stuessy, and H. Robinson. 2009. Classification of Compositae. In: Funk, V. A., A. Susanna, T. F. Stuessy, and R. J. Boyer, eds. Chapter 11. Systematics, Evolution, and Biogeography of the Compositae. International Association for Plant Taxonomy (IAPT). Vienna, Austria. pp. 171-189.

Funk, V. A., A. A. Anderberg, B. G. Baldwin, R. J. Bayer, J. M. Bonifacino, I. Breitweiser, L. Brouillet, R. Carbajal, R. Chan, A. X. P. Coutinho, D. J. Crawford, J. V. Crisci, M. O. Dillon, S. E. Freire, M. Galbany-Casals, N. Garcia-Jacas, B. Gemeinholzer, M. Gruenstaeudl, H. V. Hansen, S. Himmelreich, J. W. Kadereit, M. Kallersjo, V. Karaman-Castro, P. O. Karis, L. Katinas, S. C. Keeley, N. Kilian, R. T. Kimball, T. K. Lowrey, J. Lundberg, R. J. McKenzie, M. Tadesse, M. E. Mort, B. Nordenstam, C. Oberprieler, S. Ortiz, P. B. Pesler, C. P. Randle, H. Robinson, N. Roque, G. Sancho, J. C. Semple, M. Serrano, T. F. Stuessy, A. Susanna, M. Unwin, L. Urbatsch, E. Urtubey, J. Valles, R. Vogt, S. Wagstaff, J. Ward, and L. E. Watson. 2009. Compositae metatrees: the next generation. In: Funk, V. A., A. Susanna, T. F. Stuessy, and R. J. Boyer, eds. Chapter 14. Systematics, Evolution, and Biogeography of the Compositae. International Association for Plant Taxonomy (IAPT). Vienna, Austria. pp. 747-777.

Glemin, S. and T. Bataillon. 2009. A comparative view of the evolution of grasses under domestication. New Phytologist. 183: 273-290.

GPWG, Barker, N. P., L. G. Clark, J. I. Davis, M. R. Duvall, C. Hsiao, E. A. Kellogg, H. P. Linder, R. J. Manson-Gamer, S. Y. Matthews, M. P. Simmons, R. J. Soreng, and R. E. Spangler. 2001. Phylogeny and subfamilial classification of the grasses (Poaceae). Annals of the Missouri Botanical Garden. 88(3): 373-457.

Gruenstaeudl, M., E. Urtubey, R. J. Jansen, R. Samuel, M. H. J. Barfuss, and T. F. Stuessy. 2009. Phylogeny of Barnadesioideae (Asteraceae) inferred from DNA sequence data and morphology. Molecular Phylogenetics and Evolution. 51: 572-587.

Hilu, K. W., T. Borsch, K. Muller, D. E. Soltis, P. A. Soltis, V. Savolainen, M. W. Chase, M. P. Powell, L. A. Alice, R. Evans, H. Sauquet, C. Neinhuis, T. A. B. Slotta, J. G. Rohwer, C. S. Campbell, and L. W. Chatrou. 2003. Angiosperm phylogeny based on MATK sequence information. American Journal of Botany. 90(12): 1758-1776.

Jansen, R. K. and J. D. Palmer. 1987. A chloroplast DNA inversion marks an ancient evolutionary split in the sunflower family (Asteraceae). Proceedings of the National Academy of Sciences. USA. 84: 5818-5822.

Jansen, R. K. and D. D. Palmer. 1988. Phylogenetic implications of chloroplast DNA restriction site variation in the Mutisieae (Asteraceae). American Journal of Botany. 75: 753-766.

Jansen, R. K., Z. Cai, L. A. Raubeson, H. Daniell, C. W. dePamphilis, J. Leebens-Mack, K. F. Muller, M. Guisinger-Bellian, R. C. Haberle, A. K. Hansen, T. W. Chumley, S-B. Lee, R. Peery, J. R. McNeal, J. V. Kuehl, and J. L. Boore. 2007. Analysis of 81 genes from 64 plastid genomes resolves relationships in angiosperms and identifies genome-scale evolutionary patterns. Proceedings of the National Academy of Sciences. USA. 104(49): 19369-19374.

Ji, Q., H. Li, L. M. Bowe, Y. Liu, and D. W. Taylor. 2004. Early Cretaceous Archaefructus eoflora sp. nov. with bisexual flowers from Beipiap, Western Liaoning, China. Acta Geologica Sinica. 78(4): 883-896.

Jones, S. B. and A. E. Luchsinger. 1986. Plant Systematics. 2nd edition. McGraw-Hill Book Co. New York.
Judd, W. S., C. S. Campbell, E. A. Kellogg, P. F. Stevens, and M. J. Donoghue. 2002. Plant Systematics: A Phylogenetic Approach. Second Edition. Sinauer Associates, Inc. Sunderland, MA

Mathews, S. and M. J. Donoghue. 2000. Basal angiosperm phylogeny inferred from duplicate phytochromes A and C. International Journal of Plant Sciences. 161:S41-S55.

Matsuoka, Y., Y. Vigouroux, M. M. Goodman, J. G., E. Buckler, and J. Doebley. 2002. A single domestication for maize shown by multilocus microsatellite genotyping. Proceedings of the National Academy of Science. USA. 99(9): 6080-6084.

Moore, M. J., C. D. Bell, P. S. Soltis, and D. E. Soltis. 2007. Using plastids genome-scale data to resolve enigmatic relationships among basal angiosperm. Proceedings of the National Academy of Sciences, USA. 104(49): 19363-19368.

Panero, J. L. and V. A. Funk. 2008. The value of sampling anomalous taxa in phylogenetic studies: Major clades of the Asteraceae revealed. Molecular Phylogenetics and Evolution. 47: 757-782.

Philippe, M., B. Gomez, V. Girard, C. Coiffard, V. Daviero-Gomez, F. Thevenard, J-P. Billon-Bruyat, M. Guiomar, J-L. Latil, J. Le loeuff, D. Nedaudeau, D. Olivero, and J. Schlogl. 2008. Woody or not woody? Evidence for early angiosperm habit from the Early Cretaceous fossil wood record of Europe. Paleoworld. 17: 142-152.

Piperno, D. R. and H-D. Sues. 2005. Dinosaurs dined on grass. Science. 310: 1126-1128.

Prasad, V., C. A. E. Stromberg, H. Alimohammadian, A. Sahni. 2005. Dinosaur coprolites and early evolution of grasses and grazers. Science. 310: 1177-1180.

Qiu, Y. L., J. H. Lee, F. Bernasconi-Quadroni, D. E. Soltis, P. S. Soltis, M. Zanis, E. A. Zimmer, Z. D. Chen, V. Savolainen, and M. W. Chase. 1999. The earliest angiosperms: evidence from mitochondrial, plastid and nuclear genomes. Nature. 402:404-407.

Qiu, Y. L., J. H. Lee, F. Bernasconi-Quadroni, D. E. Soltis, P. S. Soltis, M. Zanis, E. A. Zimmer, Z. D. Chen, V. Savolainen, and M. W. Chase. 2000. Phylogeny of basal angiosperms: Analyses of five genes from three genomes. International Journal of Plant Sciences. 161:S3-S27.

Qiu, Y.L., L. Libo, B. Wang, Z. Chen, V. Knoop, M. Groth-Malonek, O. Dombrovska, J. Lee, L. Kent, J. Rest, G.F. Estabrook, T.A. Hendry, D.W. Taylor, C.M. Testa, M. Ambros, B. Crandall-Stotler, R.J. Duff, M. Stech, W. Frey, D. Quandt, and C.C. Davis. 2006. The deepest diverges in land plants inferred from phylogenomic evidence. Proceedings of the National Academy of Sciences. 103:15511-15516.

Qiu, Y.L., L. Libo, B. Wang, Z. Chen, O. Dombrovska, J. Lee, L. Kent, R. Li, R. Jobson, T. A. Hendry, D. W. Taylor, C. M. Testa, and M. Ambros. 2007. A nonflowering land plant phylogeny inferred from nucleotide sequences of seven chloroplast, mitochondrial, and nuclear genes. International Journal of Plant Science. 168(5): 691-708.

Ramirez, S. R., B. Gravendeel, R. B. Singer, C. R. Marshall, and N. E. Pierce. 2007. Dating the origin of the Orchidaceae from a fossil orchid with its pollinator. Nature. 448: 1042-1045.

Rothwell, G. W., W. L. Crepet, and R. A. Stockey. 2009. Is the anthophyte hypothesis alive and well? New evidence from the reproductive structures of Bennettitales. American Journal of Botany. 96(1): 296-322.

Saarela, J. M., H. S. Rai, J. A. Doyle, P. K. Endress, S. Mathews, A. D. Marchant, B. G. Briggs, and S. W. Graham. 2007. Hydatellaceae identified as a new branch near the base of the angiosperm phylogenetic tree. Nature. 446: 312-315.

Soltis, P. S., D. E. Soltis, and M. W. Chase. 1999a. Angiosperm phylogeny inferred from multiple genes as a tool for comparative biology. Nature. 402:402-404.

Soltis, D. E., P. S. Soltis, M. W. Chase, M. E. Mort, D. C. Albach, M. Zanis, V. Savolainen, W. H. Hahn, S. B. Hoot, M. F. Fay, M. Axtell, S. M. Swensen, L. M. Prince, W. J. Kress, K. C. Nixon, and J. S. Farris. 2000. Angiosperm phylogeny inferred from 18S rDNA, rbcL, and atpB sequences. Botanical Journal of the Linnean Society 133:381-461.

Sun, G., Q. Ji, D. L. Dilcher, S. Zheng, K. C. Nixon, and X. Wang. 2002. Archaefructaceae, a new basal angiosperm family. Science. 296(5569): 899-904.

Takhtajan, A. 1997. Diversity and Classification of Flowering Plants. Columbia University Press. New York.
Wallace, A. R. 1867. Creation by law. The Quarterly Journal of Science. 4: 470-488.

Wang, X., S. Duan, B. Geng, J. Cui, and Y. Yang. 2007. Schmeissneria: a missing link to angiosperms? BioMedCentral Evolutionary Biology. 7-14: (13 pages).

Zanis, M. J., D. E. Soltis, P. S. Soltis, S. Mathews, and M. J. Donoghue. 2002. The root of the angiosperms revisited. Proceedings of the National Academy of Sciences. U.S.A. 99:6848-6853.

This name is of our invention and does not imply that the groups included are monophyletic.

By Jack R. Holt. Last revised: 04/06/2014


FIGURE 3. Swamp Buttercup (Ranunculus septentrionalis). Plant in full flower from wet lowland Pennsylvania woodland. Image from the Systematic Biology Image Archive.	FIGURE 4. Ranunculus flower in long section illustrates salient features of the flower with petaloid stamens, many petals, sepals, and many simple pistils. Image from the Systematic Biology Image Archive.	FIGURE 5. Papaver somniferum, Opium Poppy in flower illustrating the characteristic delicate petals, multiple stamens, and box-like gynoecium. Image from the Systematic Biology Image Archive.	FIGURE 6. Dicentra cucullaria, Dutchman’s Breeches, a common spring ephemeral in the Pennsylvania woodlands. This is a zygomorphic member of the poppy family. Image from the Systematic Biology Image Archive.


FIGURE 8. Vitis vinifera, Wine Grapes in fruit. Image from Fir0002 used according to the GFDL License.	FIGURE 9. Euphorbia pulcherrima, Poinsettia floral display. Image by Andre Karwath and used according to the GFDL License.	FIGURE 10. Hevea braziliensis, Rubber. A plantation worker in the Philippines harvesting latex. Image by Randy C. Bunney and used according to the GFDL License.	FIGURE 11. Ricinus communis, Castor Bean in flower and fruit Image by Alvesgaspar and used according to the GFDL License.	FIGURE 12. Euphorbia pulcherrima, Poinsettia flowers in their diminutive inflorescences. Note that ate stamens are separate flowers from the stalked pistilate flower. The inflorescences are subtended by showy bracts. Image in the Public Domain.


FIGURE 13. Viola odorata, Johnny Jump Up with spring flowers. Image by H. Zell and used according to the GFDL License.	FIGURE 14. Viola odorata, Johnny Jump Up open capsule. Image by Rasbak and used according to the GFDL License.	FIGURE 15. Populus canadensis, staminate catkins of Poplar. Image by Rasbak and used according to the GFDL License.	FIGURE 16. Pisum sativum, Garden Pea in flower. Image by Rasbak and used according to the GFDL License.	FIGURE 17. Pisum sativum, Garden Pea in fruit. Image by Rasbak and used according to the GFDL License.


FIGURE 18. Mimosa pudica, Mimosa in flower. Image by Eric Hunt and used according to the GFDL License.	FIGURE 19. Acasia collinsii, Acasia with hollow thorns with symbiotic ants. Image by Kurt Stuber and used according to the GFDL License.	FIGURE 20. Cercis canadensis, Red Bud in flower. Image by Sballal and used according to the GFDL License.	FIGURE 21. Fragaria, Garden Strawberry in flower and an immature fruit. Image by Moja and used according to the GFDL License.	FIGURE 22. Rosa, Rose hip in longitudinal section. Image by Frank Vincentz and used according to the GFDL License.


FIGURE 23. Spiraea japonica, plant in flower, fruit, and bud. Image by Alan Pascoe and used according to the GFDL License.	FIGURE 24. Malus domestica, Pome of Sundown apple and in long section. Image by Fir 0002 and used according to the GFDL License.	FIGURE 25. Prunus persica, Drupe of Autumn Red Peaches with the pit exposed. Image by the USDA and in the Public Domain.	FIGURE 26. Dryas drummondii, Alpine plant that resembles strawberry. Image by Kurt Stuber and used according to GFDL License.	FIGURE 27. Ficus carica, fruit of the Brown Turkey Fig in long section. The synconium has the fruits on the inside of a receptacle that folds in on itself. Image by Shadle and used according to GFDL License.


FIGURE 28. Artocarpus altilis, Breadfruit in fruit, which is a multiple. Image by Hans Hillewaert and used according to GFDL License.	FIGURE 29. Cucumis sativus, Cucumber with staminate flowers and many pepos. Image by USDA and in the Public Domain.	FIGURE 30. Castanea sativa, Staminate catkins and ovulate inflorescences (top center) of the Sweet Chestnut. Image by Fir 0002 and used according to the GFDL License.	FIGURE 31. Juglans nigra, chambered pith of Black Walnut. Image by MPF and used according to the GFDL License.


FIGURE 33. Capsella bursa-pastoris, a weedy mustard displaying the characteristic rosette of leaves. Image by Rasbak and used according to the GFDL License.	FIGURE 34. Aubrieta deltoidea, Purple Rock Cress in flower displaying the characteristic petals in a cross. Image in the Public Domain.	FIGURE 35. Cardamine impatiens, Narrow-Leaved Bittercress with mature siliques. Image by Sarefo and used according to the GFDL License.	FIGURE 36. Theobroma cacao, Cacao in fruit, the seeds of which produce chocolate. Image by Luisovalles and used according to the GFDL License.


FIGURE 37. Corchorus trilocularis, Jute in flower. The fibers from this plant are used for making inexpensive strong thread and cording. This photo was taken in India. Image by J. M. Garg and used according to the GFDL License.	FIGURE 38. Hibiscus rosa-sinensis, Hibiscus in flower illustrating the attachments of the filaments to the style. This photo was taken in Tanzania. Image by Muhammad Mahdi Karim and used according to the GFDL License.	FIGURE 39. Acer pseudoplatanus, Norway Maple leaves. Image by Willow and used according to the GFDL License.	FIGURE 40. Citrus sinensis, Sweet Orange in flower and fruit. Image by Ellen Levy Finch and used according to the GFDL License.


FIGURE 42. Opuntia littoralis, a cactus native to southern California. The plant is in fruit (called prickly pears). Image by Stan Shebs and used according to the GFDL License.	FIGURE 43. Hylocereus undatus, an epiphytic cactus flower. The flower opens only a few hours during one night. The flowers are pollinated by bats and hawkmoths. These are widely cultivated to produce dragonfruit. Image by Milna Zinkova and used according to the GFDL License.


FIGURE 45. Vaccinium species in fruit. Top Right: Cranberries. Bottom Right: Lingonberries. Bottom Left: Blueberries. Top Left: Red Huckleberries. Image by Kazorpal and used according to the GFDL License.	FIGURE 46. Kalmia latifolia, Mountain Laurel in flower. Image by Arx Fortis and used according to the GFDL License.	FIGURE 47. Solanum lycopersicum, Garden Tomato in flower. This flower shows many of the characteristics of the Solanaceae: five petals fused at the base and style surrounded by five stamens. Image by Victor M. Vincente Selvas and realesed into the Public Domain.


FIGURE 49. Nicotiana tabacum, Tobacco in flower. Image by Joachim Mullerchen and used according to the GFDL License.	FIGURE 50. Coffea arabica, illustration of coffee in bud, flower, and fruit. Image by Francisco Manuel Blanco, from Flora de Filipinas (1880) in the Public Domain.	FIGURE 51. Gardenia jasminoides, Gardenia in flower. This plant has been cultivated more than 1000 years in China. Image by Kenpai and used according to the GFDL License.	FIGURE 52. Mentha longifolia, Horsemint in flower. Image by Michael Becker and used according to the GFDL License.	FIGURE 53. Tectona longifolia, Teak in flower. The photo was taken in Kolkata, West Bengal, India. Image by J. M. Garg and used according to the GFDL License.


FIGURE 60a. Bidens showing ray and disk florets in a single inflorescence. This image was by Marshman and used according to the GFDL License.	FIGURE 60b. Diagram of ray floret. The floret is zygomorphic and viewed from the side. A= ovulary; B= pappus; C= theca (sterile stamens); D= ligule (fused corolla); E= style. Image by Carol Spears and used according to the GFDL license.	FIGURE 60c. Diagram of disk floret. The floret is actinomorphic and viewed from the side. A= ovulary; B = corolla; C= fused stamens; D= style. Image by Jo Jan and used according to the GFDL license.


FIGURE 55. Daucus carota, Carrot in flower. This plant when it becomes a weed is called Queen Anne’s Lace. The inflorescence is a compound umbel. Image by Kurt Stuber and used according to the GFDL License.	FIGURE 56. Hedera helix, English Ivy growing on walls of High Castle, a 13th Century Teutonic Monastic Castle in Malbork, Poland. This is a World Heritage site. Image by Der Hexer and used according to the GFDL License.	FIGURE 57. Cichorium pumilum, Chickory in flower. This plant is a common road-side weed, but cultivated forms are known as endive. The roots also are harvested and used as a coffee substitute. Image by Lorsh and released into the Public Domain.	FIGURE 58. Helianthus annuus, Sunflower in flower showing both disk and ray flowers. Image by Jon Sullivan and released into the Public Domain.


FIGURE 59. Taraxacum officinale, Dandelion in flower with a head of ray flowers (top) and fruit showing the ball made of the collective pappus attached to all of the achenes (bottom). Image by Jon Sullivan and released into the Public Domain.	FIGURE 62. Chuquiraga opprsitifolia, one of the most primitive composites. This plant is native to Argentina. Image by Franz Xaver and used according to the GFDL License.	FIGURE 63. Cirsium vulgare, Spear Thistle is one of the most common weeds of Eurasia. The head is formed of disk flowers and subtended by a globose involucre. Image by Olivier Pichard and used according to the GFDL License.	FIGURE 64. Aster alpinus, Alpine Aster is native to the Alps. This plant makes inflorescences that have both disk and ray flowers. Image by Michael Schmid and used according to the GFDL License.

CLASS ASTEROPSIDA (Brongniart 1843)

Document Footer