Major structural details of hornworts, with emphasis on the sporophyte. Figure A is a habit sketch of a Phaeoceros plant that is producing sporophytes. Figure B illustrates the simple stomata with the paired guard cells on the gametophyte thallus of Anthoceros. Figure C shows the structure of a stomate on the sporophyte of Anthoceros. Figures D&E show details of the anatomy of an Anthoceros sporophyte. Note that much of the tissue is sterile. Also, note the foot and intercalary meristem in Figure E. The structures of the antheridia (Figure G) and of the archegonia (Figure H) are relatively simple compared to those of the liverworts and mosses.