Notes on Tree Morphology: “The Difference Between a Simple and Compound Tree Leaf” by Steve Nix

Web link: https://www.thoughtco.com/simple-and-compound-tree-leaf-4051112

Shape of individual leaf – Compound Leaves

As suggested earlier in Notes on Taxonomy of Trees, “trees of the genus have the same basic flower structure and may resemble other genus members in outward appearance. Tree members within a genus can still vary significantly in leaf shape, style of fruit, the color of bark and tree form.”

There are three types of compound leaves: pinnately, double pinnately, and palmately.

Pinnately Compound - The term pinnation, when talking about a tree's leaf, refers to how multi-divided leaflets arise from both sides of a common axis, or rachis. There are three types of pinnate leaflet arrangement:

• Even-pinnate leaflet arrangement: rachis divisions on pinnately compound leaves in which leaflets sprout in pairs along the rachis without a single terminal leaflet. Also called "paripinnate."

• Odd-pinnate leaflet arrangement: rachis divisions on pinnately compound leaves in which there is a single terminal leaflet at the top of the structure rather than a terminal pair of leaflets. Also called "imparipinnate."

• Alternate-pinnatel leaflet arrangement: rachis divisions on pinnately compound leaves in which leaflets sprout alternately along the rachis, usually with a single terminal leaflet. It is also called "aternipinnada."

Double Pinnately Compound - This compound leaf arrangement has several names, including bi-pinnate, double pinnate, and twice pinnate. In this case, leaflets are arranged on what are actually secondary stems, which grow off a main stem, or rachis.

Palmately Compound - The palmately compound leaf is easy to recognize because it looks like a palm frond, with its distinctive hand-and-finger shape.

Publicado el agosto 26, 2020 07:39 MAÑANA por lunababy22