BI266 Lecture Notes - Lecture 4: Cork Cambium, Vascular Cambium, Primordium
Document Summary
Woody twig consists of an axis with attached leaves. Node = area of stem where leaves are attached. Alternate or spiral, opposite; attached in pairs, whorled; in groups of 3 or more. Leaf has a flattened blade and is usually attached to the twig by petiole. Will become branches or flowers in flowering plants. Number of groups of bud scales tells age of twig. Stipules = pairs, often leaf-like appendages at base of a leaf. Deciduous trees and shrubs (lose all leaves annually) = after leaves fall, have dormant axillary buds with leaf scars below. Bundle scars = mark food and water conducting tissue within leaf scars. Cells produced by stem meristem become shoot system with branches and leaves. Protects by bud scales and by leaf primordia. Leaf primordia = tiny embryonic leaves that develop into mature leaves. Ground meristem = produces pith and cortex, both composed of parenchyma.
