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HIERARCHICAL CLASSIFICATION OF THE PHYLUM PHAEOPHYTA

HIERARCHICAL CLASSIFICATION OF THE PHYLUM PHAEOPHYTA (KJELLMAN 1891)

EUKARYA> CHROMALVEOLATA> HETEROKONTAE> PHAEOPHYTA
PHAEOPHYTA LINKS

Introduction

Synoptic Description

This system is a modification of Clayton (1990), Margulis and Schwartz (1988, Pr-12; 1998, Pr-17), Sleigh et al. (1985), Bold and Wynne (1985), Graham and Wilcox (2000), Phillips et al. (2008), Silberfeld et al. (2010), de Reviers et al. (2007).

CLASS PHAEOPHYTEA

  • The phylum, PHAEOPHYTA, has a single class with 13 orders.
  • ORDER DICTYOTALES
    • Flat, branched, thalloid organisms with apical growth; sexual reproduction oogamous; isomorphic alternation of generation.
    • Dictyota, Dictyotopsis, Dilophus, Zonaria, Padina.
  • ORDER SYRINGODERMATALES
    • Isogamous. Sporophyte parenchymatous with apical/marginal growth.
    • Microzonia, Syringoderma.
  • ORDER SPHACELARIALES
    • Branched, pseudoparenchymatous; growth governed by a large apical cell; sexual reproduction isogamous to oogamous; sporophyte and gametophyte generations isomorphic.
    • Sphacelaria, Halidrys, Cystoseria, Cladostephus.
  • ORDER DESMARESTIALES
    • Trichothallic growth forms sporophyte thallus composed of large central cells and large numbers of small cortical cells; gametophyte stage, microscopic filament with oogamous reproduction.
    • Arthrocladia, Desmarestia, Himanothallus.
  • ORDER SPOROCHNALES
    • Characterized by a tuft of hairs at the end of each axis; an intercalary meristem at the bases of the hairs which produces a pseudoparenchymatous thallus; heteromorphic alternation of generation (macroscopic diploid alternating with a microscopic haploid); oogamous.
    • Sporochnus, Bellotia, Carpomitra.
  • ORDER SCYTOTHAMNALES
    • Anisogamous taxa with heteromorphic alternation of generation with a small filamentous sporophyte and a relatively large parenchymatous gametophyte.
    • Scytothamnus, Splachnidium.
  • ORDER ECTOCARPALES
    • This order has quite a range in growth form.
    • Gorup 1: Relatively small, with filamentous or pseudoparenchymatous structure; reproduction isogamous or anisogamous; complex alternation of isomorphic generations.
    • Ectocarpus, Giffordia, Feldmannia, Streblonema, Pilayella, Analipus.
    • Group 2: These have a heteromorphic alternation of generation (small haploid alternating with a macroscopic diploid); heterotrichous to pseudoparenchymatous; isogamous.
    • Chordaria, Eudesme, Cladosiphon, Myrionema, Elachista, Leathesia.
    • Group 3: Like the Dictyosiphonales except the vegetative cells have a single large chloroplast which has a pyrenoid; only plurilocular organs in the macroscopic, diploid form.
    • Scytosiphon, Petalonia.
    • Group 4: Heteromorphic alternation of generation (macroscopic diploid alternating with a microscopic haploid); parenchymatous; isogamous.
    • Dictyosiphon, Stictyosiphon, Punctaria, Soranthera.
  • ORDER LAMINARIALES
    • Very large, parenchymatous; diploid sporophytic thallus alternates with microscopic haploid gametophytes with oogamous reproduction; sporophyte normally attached with intercalary growth and may reach length of 50m. The kelps.
    • Laminaria, Hedophyllum, Agarum, Costaria, Chorda, Dictyoneurum, Postelsia, Nereocystis, Macrocystis, Alaria, Pterygophora, Egregia, Eisenia, Undaria, Ecklonia, Saccharina, Pelagophycus.
  • ORDER ASCOSERIALES
    • Isogamous sexual reproduction; sporophyte parenchymatous with intercalary growth.
    • Ascoseira.
  • ORDER RALFSIALES
    • Thallus crustose.
    • Analipus, Ralfsia.
  • ORDER TILOPTERIALES
    • Group of filamentous forms which resemble the Ectocarpales; parenchymatous at the base, trichothallic division above; monosporangia; isomorphic alternation of generation; oogamous.
    • Tilopteris, Haplospora, Sacchorhiza, Phyllariopsis.
    • Trichothallic growth forming parenchymatous thallus; isomorphic or heteromorphic alternation of generation; anisogamous reproduction.
    • Cutleria, Zanardinia.
  • ORDER NEMODERMATALES
    • Thallus crustose.
    • Nemoderma.
  • ORDER FUCALES
    • Growth of diploid parenchymatous gametophyte governed by recessed apical cell giving rise to flattened but branched thallus; sexual reproduction oogamous with gametic meiosis. Shore weeds; wracks.
    • Fucus, Ascophyllum, Pelvetia, Sargassum, Cystoseira, Homosira.
    • These organisms grow by diffuse division, not by the division of apical cells and their photosynthetic cells are elongate with 2 chloroplasts per cell.
    • Durvillaea.
LITERATURE CITED

Bold, H. C. and M. J. Wynne. 1985. Introduction to the Algae. 2nd Edition. Prentice-Hall, Inc. Englewood Cliffs. NJ.

Bold, H. C., C. J. Alexopoulos, and T. Delevoryas. 1987. Morphology of Plants and Fungi. 5th Edition. HarperCollins Publishers, Inc. New York.

Cavalier-Smith, T. 1989. The Kingdom Chromista. In: Green, J.C., B. S. C. Leadbeater, and W. L. Diver, eds. The Chromophyte Algae: Problems and Perspectives. Systematics Association Special Volume No. 38. Clarendon Press. Oxford. pp. 381-407.

Clayton, M. N. 1990. Phaeophyta. In: Margulis, L., J. O. Corliss, M. Melkonian, and D. J. Chapman, eds. 1990. Handbook of the Protoctista; the Structure, Cultivation, Habits and Life Histories of the Eukaryotic Microorganisms and Their Descendants Exclusive of Animals, Plants and Fungi. Jones and Bartlett Publishers. Boston . pp. 698-714.

Dodge, J. D. 1973. The fine structure of algal cells. Academic Press. New York.

Graham, L. E., and L. W. Wilcox. 2000, Algae: Prentice Hall, Upper Saddle River, NJ.

Margulis, L. and K. Schwartz. 1988. Five kingdoms, an illustrated guide to the phyla of life on earth. 2nd Edition. W.H. Freeman and Co. New York.

Margulis, L. and K. Schwartz. 1998. Five kingdoms, an illustrated guide to the phyla of life on earth. 3rd Edition. W. H. Freeman and Company. New York.

O’Kelly, C. J. 1989. The evolutionary origins of the brown algae: information from studies of motile cell ultrastructure. In: Green, J.C., B.S.C. Leadbeater, and W.L. Diver, eds. The chromophyte algae, problems and perspectives. Systematics Association Special Volume No. 38. Clarendon Press. Oxford. pp. 255-278.

Patterson, D. J. 1999. The diversity of eukaryotes. American Naturalist. 154 (Suppl.): S96–S124.

Scagel, R. F., R. J. Bandoni, G. E. Rouse, W. B. Schofield, J. R. Stein, and T. M. C. Taylor. 1984. Plant Diversity, An Evolutionary Approach. Wadsworth Publishing Co. Belmont, CA.

Sleigh, M.A., J.D. Dodge and D. J. Patterson. 1984. Kingdom Protista. In: Barnes, R.K.S., ed. A Synoptic Classification of Living Organisms. Sinauer Associates, Inc. Sunderland, Mass.

Taylor, F. J. R. 1976. Flagellate phylogeny: a study in conflicts. Journal of Protozoology. 23: 28-40.

Van Den Hoek, C., D. G. Mann, and H. M. Jahns. 1995. Algae, an introduction to phycology. Cambridge University Press. Cambridge.
By Jack R. Holt. Last revised: 02/28/2012
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