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Gymnosperms(non-flowering seed
plants)
EKU BIO 131
Gymnosperms
• Phylum Ginkgophyta Ginkgo – the only species is Ginkgo biloba
• Phylum Cycadophyta the cycads
• Phylum Coniferophyta (or Pinophyta) the conifers
• Phylum Gnetophyta the gnetophytes
Ginkgoovule and seed development
Ginkgophyta
Leaves and seeds
microsporangiaon male tree
ripe seeds
cleaned seeds (sometimescalled “Ginkgo nuts”)
germinating seeds
Cycadophyta sporophytes
Two explorers with the only wildspecimen of Encephalartos woodii everdiscovered. It was first discoveredin the early 1700s.
Cycad cones
seed cones
pollen cones
Encephalartoswoodii
Cycad sporangia and coralloid roots
note microsporangium,tapetum, microspores
note integuments, megasporangium,Female gametophyte
coralloid roots root with zone of symbiotic cyanobacteria
ConiferophytaPollen cone buds of Japanese Black Pine (at about meiosis time)
photo by Ross Clark
pollen conebuds(the dark spotsare the tips ofthe microsporophylls)
buds containingneedles
Pine pollen developmentbe able to identify all structures
Coniferophyta
Pine ovule developmentbe able to identify all structures
Coniferophyta
Gnetophyta: Gnetum
notice stamens and ovules (plant is monoecious)
seeds
Gnetophyta: Ephedra
male female
(Ephedra is dioecious.)
seeds
Ephedrine is potentiallydangerous.
Gnetophyta: Welwitschia
Welwitschia is definitely one of the world’s most unusual plants!
Here is Welwitschia’s only habitat: the Namibian Desert, one of the driest deserts in the world.
Welwitschia is one ofThe world’s rarest plants. Most of the following photos were taken by Terry Huff, an EKU graduate student.
photo by Terry Huff
Gnetophyta: Welwitschia
photo by Terry Huff
Welwitschia has two leaves. They have basal meristems. The leaves eventually become separated into tattered segments.
Welwitschia is dioecious. This is a female plant. Note the ovulate (seed) cones, and compare them with the pollen cones on the next slide.
Here is a young plant. Young plants are extremely rare.Note the two leaves.
photo by Terry Huff
Gnetophyta: Welwitschia
photo by Terry Huff
Here is a male plant. Note the smaller pollen cones.
photo by Terry Huff
Gnetophyta: Welwitschia
photo by Terry Huff
photo by Terry Huff
Here are some female (seed)cones, together with the small bugs that live on Welwitschiaand may help to pollinate it.
photo by Terry Huff
Gnetophyta: Welwitschia
photo by Terry Huff
photo by Terry Huff
Here are some female cones, together with the small bugsthat live on Welwitschia and may help to pollinate it.
Here are some very young seed cones, at about pollination time.
photo by Terry Huff
Gnetophyta: Welwitschia
photo by Terry Huff
photo by Terry Huff
Here is another nice photo of a plant loaded with seed cones. Very few of the seeds germinate, because of the extreme environmental conditions in the Namibian Desert.
photo by Terry Huff
Why so many photos of Welwitschia?
-- because these photos by Terry Huff are some of the best photos ever taken of Welwitschia in its native habitat. They are better than any other photos you will find in any textbooks or on the web.
Terry said he was told there were fewer than 20 Welwitschia plantsremaining in their native habitat.