IB 103 - Gymnosperms

gymnosperm seeds provide

protective seed coat, food source for the embryo, ability to survive unfavorable conditions in dormancy

gymnosperm means

naked seeds

seeds are on sporophylls often in

cones

pollen cones produce

pollen grains

seed cones produce

seeds

__ becomes seed coat after fertilization

integument

seeds hold the female gametophyte in the ovule containing the

nucellus

source of embryo nutrition in seed

nucellus

phylum pinophyta - conifers

dominant trees in coniferous forests

leaves needlelike and in clusters called fasicles

thick cuticle, sunken stomata, hypodermis and epidermis

tracheids but no vessel elements

softwood

2 spore types in phylum pinophyta

microspores: make pollen grains, each pollen grain has 4 cells, generative cell gives rise to sperm

megaspores: megasporangia surrounded by integument that has micropyle (pore)

phylum ginkgophyta - ginkgos

1 living species

reproduce similar to pines

dioecious

seeds have fleshy coat with rank odor at maturity

phylum cycadophyta - cycads

tall unbranched trunks

large pinnately divided leaves

pollinated by beetles

dioecious

appear to be cross between palm and fern

strobilus found in plant center

phylum gnetophyta - gnetophytes

have vessels in xylem

gnetum: vine-like plants with broad leaves