Lecture #9- Progymnosperms and Gymnosperms Flashcards
What did progymnosperms invent?
Wood
-once trees became truly woody, they invented seeds
What is the oldest living plant with seeds?
Gymnosperms
What is true wood?
Secondary Phloem and Xylem
What is bifacial vascular cambium?
Surface in the stem that produces on both sides, a growing tissue
Did progymnosperms have spores?
Yes they were spore bearing
Characteristics of the pro gymnosperm Aneurophytales?
- protostele
- secondary growth
- highly branched
- reproduced by spores (homosporous)
What is a gymnosperm?
Plants that have naked seeds exposed on the surface of sporophylls and have no ovary wall
What is an ovule?
a megasporangium, which produces the female megaspore, within 1-2 layers of tissue called the integument
- mom produces the ovule with 2n tissue
- magasporangium starts 2n but turns into a spore which is just n
What are sporophylls the same thing as?
cupules
-the modified leaves that the spores are on
What does the ovule turn into?
A seed, in seed ferns
Characteristics of Cycads?
- fern like foliage
- short stems with little secondary growth
- Spiral leaves
- Primary roots well developed (inhabited dry areas)
- Had secondary roots growing above ground
- cyanobacterial association
- heterospore (male and female plant)
- only one ovule develops into a zygote
What are microgametophytes?
wind dispersed pollen
Characteristics of Ginkgos?
- Has secondary growth aka true wood
- Pollen produced in microstrobili and microsporangia
- 2-4 archegonium per ovule
Characteristics ofGnetophyta
-all species are different enough that they all have their own order
-Xylem has vessels (independently evolved)
-Ephedra had scale like leaves
-mono-or dioecious
-Microstrobili and microsporangia (wind borne pollen)
-Megastrobili have 4-7 bracts
-ovary can have 2-3 archegonia
-Hard black seeds surrounded by red fleshy tracts if megastrobili
-
What are cones?
Modified leaves
