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Biology 337: Divisions ( Glossary \| Divisions )
Taken Spring 2005, with Dr. Plant. Information here is based primarily upon notes from class but some from external sources like the web.

Hepatophyta	Anthocerophyta	Bryophyta	Psilotophyta	Lycophyta
Sphenophyta	Pterophyta	Rhyniophyta	Zosterophyllophyta	Trimerophytophyta
Cycadophyta	Gingkophyta	Coniferophyta

age	permian
division-name	Cycadophyta
evolution	evolved from seed ferns
gametophyte	.
habit	.
leaves	megaphyll Present as crown at apex of plant Pinate with single series of leaflets. Only gymnosperm to possesss fern-life leaves. Present as crown at apex of plant
life-cycle	Homosporous and Heterosporous Are dioecious. Cones are usually compact but also produce the largest cones of athe seed plants. Male cones have thick scale-like microsporophylls where the microsporangia are cluster on the lower surface. The megasprophylls of female cones are reduced leaves. Megasporangia are located laterally (look up more on this) The microgametophyte when dispersed is a 3-celled pollen structure. Containing a Tube cell, a generative cell (for sperm) and a prothallial cell. Not sure how pollination occurs. Wind or possibly weevil co-evolution. Pollen lands on an ovule and enters via the pollen droplet. Pollen germinates and pollen tube invades tissue of nucellus. Gingko and Cycads are the only gymnosperms to produce motile sperm. In the megagametophyte, a single megaspore the nucellus gives rise to 4 spores but three are degraded. Cells at micropyle end gives rise to archegonia, which produce the largest egg in the plant kingdom The egg will develop in the megagametophyte and the seed that is shed is ready for immediate germination rather than entering a period of domancy... considered a primitive trait.
links	Handy quick reference
members	11 genera remain. Extremely slow growing. Short plants with squat stem covered in leaf bases from shed leaves
rhizome	.
roots	Produce a root system derived from embryonic root. Also produce negatively geotropic roots. (roots associate with N2-fixing cyanobacteria)
sporangia	.
stems	does not generally branch wide cortex and large pith 2ndary growth is atypical. Produces small amounts of vascular tissue. Vascular tissue is dominated by parenchymal cells. Stem is not characteristic of the gymnosperms
stomata	.
traits	.
vascular-system	eustele

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