Search results
Results from the WOW.Com Content Network
Chart illustrating leaf morphology terms. The following terms are used to describe leaf morphology in the description and taxonomy of plants. Leaves may be simple (that is, the leaf blade or 'lamina' is undivided) or compound (that is, the leaf blade is divided into two or more leaflets). [1]
Leaflet – a separate blade, among others, of a compound leaf; Ligule – a projection from the top of the sheath on the adaxial side of the sheath-blade joint in grasses. Midrib – the central vein of the leaf blade. Midvein – the central vein of a leaflet. Petiole – a leaf stalk supporting a blade and attaching to a stem at a node.
(of a compound leaf) Having precisely two leaflet s, usually in a symmetrical pair, e.g. a leaf of Colophospermum mopane. Compare jugate lobed leaf, e.g. most species of Bauhinia. bifusiform Fusiform with a pinch in the middle. bilabiate Having two lips, e.g. the form of the petal s in many irregular flowers. bilateral 1.
The ligule is part of the leaf that is found at the junction of the blade and sheath of the leaf. It may take several forms, but it is commonly some form of translucent membrane or a fringe of hairs. The membranous ligule can be very short 1–2 mm ( Kentucky bluegrass , Poa pratensis ) to very long 10–20 mm ( Johnson grass , Sorghum ...
Two basic forms of leaves can be described considering the way the blade (lamina) is divided. A simple leaf has an undivided blade. However, the leaf may be dissected to form lobes, but the gaps between lobes do not reach to the main vein. A compound leaf has a fully subdivided blade, each leaflet of the blade being separated along a main or ...
A hastula is a flap of tissue borne at the insertion of the blade on the petiole on the upper, lower, or both leaf surfaces [8] [9] Bifurcate fronds may also develop. The extinct Devonian seed plant Cosmosperma polyloba demonstrated the early evolutionary diversification of frond branching patterns, presenting both bifurcate and trifurcate types.
With an opposite leaf arrangement, two leaves arise from the stem at the same level (at the same node), on opposite sides of the stem. An opposite leaf pair can be thought of as a whorl of two leaves. With an alternate (spiral) pattern, each leaf arises at a different point (node) on the stem. Distichous leaf arrangement in Clivia
The leaves contain a single, unbranched vascular strand, and are microphylls by definition. [6] They are usually arranged in spirals. [ 7 ] The kidney-shaped (reniform) spore -cases ( sporangia ) contain spores of one kind only, ( isosporous, homosporous ), and are borne on the upper surface of the leaf blade of specialized leaves (sporophylls ...