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Explain the first seed-bearing plant
- a. Archaeosperma
- i. Integumentary lobes not totally fused
- Filamentous tip and sterile branch give slightly more protection
- group member of?
- a. 5 million years older (365 million years)
- i. Has two “seeds”; immature so they are called ovules
- ii. Integumentary lobes have not fused as much as Archaeosperma
- iii. Other vegetative branches called cupules
- Probably part of a group of plants called the seed fern
What are seed ferns?
- time frame
- i. No longer around; totally extinct
- ii. Existed from about 360 mil years ago to 180 mil years ago
- iii. Reached their peak about the same time that the ferns and club mosses and horsetails did, about 300 million years ago
- iv. Like small trees and considered gymnosperms (seed not enclosed in fruit; it is a naked seed); a few were vine like
- v. Seeds vary from a fraction of an inch to four inches in length
- vi. Could have been ancestral to other seed-producing plants
How would you tell the difference between the leaf of a true fern and the leaf of seed fern?
If it has sori, it’s a true fern; if it has a seed, it’s a seed fern
Nobody put the idea of fern and seed like foliage together until __.
The placement of these seeds depends on the seed fern
- 1. Seeds can do a number of things
- a. Pinnae so that one of the places you can find seeds is replacing one of the lateral pinnae
- b. The other may replace the pinnae at the end of the leaf
- c. The other is right at the tip of the pinnae
- d. Can also be lying on the surface of the pinna
Seed ferns evolved from __