BISC 337 Lecture Notes - Lecture 8: Equisetum, Equisetales, Xylem

• School: Simon Fraser University
• Department: Department of Humanities Biological Sciences
• Course: BISC 337
• Professor: Aubrey Pearson

Document Summary

Phylum: monilophytes (pteridophyta: secondary xylem, leptosporangia (sporangium that arises from a single initial cell, loss of roots & leaves (epiphytes) Name origin: equus : equus latin for horse , setum latin for bristle . Entire order represented today by the single genus equisetum: aka horsetails or scouring rush . Date back to devonian: abundant in forests of the carboniferous. Equisetum is the sole survivor of the genus: may be the oldest living genus of surviving plants, very similar to the 300-million-year-old equisetophytes. Visually unusual plants that occur as: branched forms, unbranched forms. Possess distinctive jointed aerial stems with scale-like leaves forming a sheath around the stem. Branches occur at a node and form a whorl stem are ribbed and feel rough: silica is present in epidermal cell walls. Aerial stems arise from an underground perennial rhizome. Leaves (are reduced megaphylls) fused at base to form a collar (sheath) that encircles the stem.