BISC 337 Lecture Notes - Lecture 9: Leptosporangiate Fern, Polypodiales, Microphyll
Document Summary
Phylum: monilophytes (pteridophyta: secondary xylem, leptosporangia (sporangium that arises from a single initial cell, loss of roots & leaves (epiphytes) Development of the megaphyll went hand-in-hand with increased complexity in the stele: due to complex venation in leaf, stem is either a rhizome or a short aerial stem, possess true roots. Even tree ferns with trunks of 30cm show no secondary growth: fibrous root mantle adds to the thickness of the stem. I. e. whole stem growth is due to the activity of primary meristem. 2nd largest group of extant vascular plants: anthophyta (flowering plants) are the largest group. About 11 000 living species: most species are tropical. Morphologically extremely diverse: tree ferns, epiphytes, tiny water ferns. Jan 27: diverse range in shape and size. Introducing megaphylls: frond more dissected common form. Dominate the entire plant: megaphyll is a major evolutionary advantage due to its high surface area: volume ratio, efficient photosynthesis.