BIOL 2004 Lecture Notes - Lecture 6: Pinus Contorta, Sequoia Sempervirens, Gymnosperm
30 Jan 2017
School
Department
Course
Professor
Document Summary
Lecture 6 - gymnosperms (end) & phylum coniferophyta. Scales grow closed after pollination and remain closed while the cone matures. Seeds are shed in the second autumn after pollination. An ovulate pinecone becomes quite woody as it mature. Pine seeds are winged - easy for dispersal. Seeds are frequently released by animals trying to eat the seeds. Some pines (lodge-pole pine) require intense heat for the seeds to be released: e. g. forest fires. Gymnosperms were the dominant plants in mesozoic era. Members of phylum coniferophyta, the most common gymnosperms, consist of about 50 genera of trees with approximately 550 species worldwide. Conifers include the world"s tallest and largest plants. Tallest are coast redwoods: height - 112. 34 meters (368. 6feet) Anatomically, softwood has no fibers and has thinner cell walls than the wood of most angiosperm trees. Tracheids - lack perforation plants in end walls: transports water.
