BIOL 2P93 Lecture Notes - Lecture 21: Cladistics, Vascular Bundle, Subcutaneous Tissue
24 Jan 2016
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Tallest land vascular plant is coniferous: coast redwood (sequoia sempervirens) w/ height of about 380 feet. Oldest tree: great basin bristlecone pine (pinus longaeva) dated 4,845 years old. Needle-like leaves of modern conifers allow adaptation to drought conditions. Eco advantage in some habitats + responsible for diversity during dry + cold permian period (290-245mya). Pine (pinus sp. ) tree, example for all conifers + split cladistically from all other conifer genera. Characterized by arrangement of needles unique among living conifers. Pine seedlings: needles spirally arranged + borne singly on stems. After years of growth, pine makes needles in bundles (fascicles), from 1-8 depending on species. Fascicles wrapped at base by series of small scale- like leaves. Fascicles are short shoots where apical meristem is restricted needles are morphologically determinate branch (growth of limited duration). Reactivate + grow into new shoot w/ indeterminate growth (unlimited/unrestricted). Fascicle may make roots + grow into an entire tree.
