Displaying 1 - 60 out of 159 Object(s)
| Term | Definition | |
|---|---|---|
| Acanthophyll | A spine derived from a modified leaf or leaflet; e.g, in |
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| Alternate leaves | Referring to leaves that arise from an axis singly at each node, the leaves can be either simple or compound. Compare with opposite and whorled. | |
| Anadromous | Referring to a venation pattern in which the first vein in a given segment arises on the side of the leaf segment toward the apex. |  |
| Anisophylly (anisophyllous) | With two leaves of a pair differing in shape and/ or size; this is relatively common in species of Melastomataceae.. |  |
| Bifoliolate | Referring to a compound leaf with two leaflets. | |
| Bipinnate, bipinnately compound | Twice-pinnate; e.g., leaves of many species of Fabaceae-Mimosaceae. See pinnate. |  |
| Biternate | Twice ternate, in two groups of three each; e.g., the leaves of some species of Serjania (Sapindaceae). | |
| Catadromous | Referring to a venation pattern in which the first vein in a given segment arises on the side of the leaf segment toward the base. | |
| Collective vein | A vein running along the leaf margin, such as in many species of Anthurium (Araceae). | |
| Compound leaf | Referring to a leaf which is divided into smaller units; i.e., leaflets. Opposite of simple. | |
| Contraligule | In Cyperaceae, a projection at the summit of the leaf sheath opposite the insertion of the leaf blade. |  |
| Decussate leaves | Referring to opposite leaves arranged with each succeeding pair at right angles to the pairs below and above them. |  |
| Estipulate | Without stipules. Same as exstipulate. | |
| Even-pinnate leaf | Pinnately compound leaf with an even number of leaflets; i.e., without a terminal leaflet. Same as parapinnate. |  |
| Exmedial | Away from the leaf axis. |  |
| Exstipulate | Without stipules. Same as estipulate. | |
| Foliolate | With leaflets; e.g., 3-foliolate or trifoliolate is a leaf with three leaflets. |  |
| Free nervation | Leaf veins that do not unite to form a network. Compare with anastomosing and reticulate. | |
| Heterophylly (heterophyllous) | Referring to species or individuals with leaves that differ in size or shape. See heteromorphic. |  |
| Higher order venation | All venation smaller in diameter than tertiary venation. |  |
| Homophyllous | See isophyllous. | |
| Imparipinnate leaf | Pinnate with an uneven number of leaflets, i.e., with a terminal leaflet. Same as odd pinnate. | |
| Induplicate | In Arecaceae, referring to leaflets that are V-or trough-shaped in transverse section with the apex of the V pointing downward, e.g., in the leaflets of date palms (Phoenix dactylifera). Opposite of reduplicate. | |
| Intersecondary vein | A leaf vein that is intermediate in size between secondary and tertiary veins and often runs parallel to the secondary veins that it runs between. At about the middle between the midrib and the leaf blade margin intersecondary veins start to ramify dendritically. |  |
| Intervenium | The space between the secondary veins of a leaf. | |
| Intramarginal vein | A vein close to and parallel to the margin of a leaf. |  |
| Isodromous | Referring to a venation pattern in which the first two veins in a given leaf segment arise opposite one another. Compare with anadromous and catadromous. |  |
| Isophyllous | Having leaves all of one shape and size. Same as homophyllous. | |
| Jugum (plural = juga) | A pair of leaflets on a pinnately compound leaf. | |
| Lateral leaflet | In a pinnately compound leaf, the leaflets at inserted along the rachis. Note that pinnately compound leaves with lateral leaflets can be either imparipinnate ( = odd pinnate) or paripinnate (= even pinnate) depending on if there is a terminal or there is not a terminal leaflet, respectively. |  |
| Lateral vein | Same as secondary vein. | |
| Leaf | A green, expanded stucture usually consisiting of a petiole and a blade but sometimes without a petiole in which photosynthesis takes place. When a petiole is absent the leaf is called sessile. |  |
| Leaf apex acuminate | Gradually tapering to an acute apex with the sides being concave. |  |
| Leaf apex acute | Sharp; usually referring to the apex of a flattened structure (such as a leaf) in which the two sides are straight and, when they meet, form an angle that is always less than 90° | |
| Leaf apex attenuate | Tapering very gradually to a narrow tip. | |
| Leaf apex emarginate | Markedly notched, such as the apex of a leaf or other structure. | |
| Leaf apex mucronate | A sharp point at the apex of a leaf or a similar structure, e.g., a bract. | |
| Leaf apex obtuse | Blunt, usually referring to the apex of a flattened structure (such as a leaf) in which the two sides are straight and, when they meet, form an angle greater than 90°. | |
| Leaf apex retuse | Notched slightly at the apex. | |
| Leaf apex rounded | Referring to a leaf blade base that is curved at the apex with an angle greater than 90 degrees at the point where the two sides meet. | |
| Leaf apex truncate | Referring to an apex or base that terminates abruptly in a nearly straight horizontal edge. | |
| Leaf asymmetrical | Referring to the form of a leaf in relation to the midrib, if the blade on each side of the midrib is unequal the leaf is asymmetrical. |  |
| Leaf base acute | Sharp; referring to the base of a leaf blade in which the two sides are straight and, when they meet, form an angle that is always less than 90°. |  |
| Leaf base asymmetric | Referring to a leaf base in which the two sides do not attach to the petiole at the same place, one is attached than the other. |  |
| Leaf base cordate | Heart-shaped at the base of a leaf blade. A cordate leaf blade always has a cordate base but a cordate leaf base may not always be associated with a cordate leaf blade. | |
| Leaf base cuneate | Wedge-shaped; referring to the base of a leaf blade of which the angle formed by the meeting of the margins is less than 90°. | |
| Leaf base decurrent | Referring to a leaf blade base that extends down the petiole. | |
| Leaf base lobate (lobed) | A rounded projection arising from the base of a leaf blade. | |
| Leaf base obtuse | Blunt, referring to the the base of a leaf blade in which the two sides are straight and, when they meet, form an angle greater than 90°. | |
| Leaf base rounded | Referring to a leaf blade base that is curved at the apex with an angle greater than 90 degrees at the point where the two sides meet. | |
| Leaf base sagittate | The base of a leaf blade shaped like an arrowhead. |  |
| Leaf base truncate | Referring to the base of a leaf blade that terminates abruptly in a nearly straight horizontal edge. | |
| Leaf blade | The expanded portion of a leaf, it and the petiole combined equal the leaf. Same as lamina. |  |
| Leaf flush | The expansion of new leaves. |  |
| Leaf gap | A region of parenchyma in the vascular tissue of a stem that is located above the level where a leaf trace diverges from the stem toward the leaf. |  |
| Leaf lamina | The expanded portion of a leaf, it and the petiole combined equal the leaf. Same as leaf blade. | |
| Leaf margin crenate | Referring to a leaf blade margin with teeth rounded at the apex. Compare with serrate. |  |
| Leaf margin dentate | Referring to a leaf margin with sharp teeth oriented at right angles to the central axis of the leaf blade. | |
| Leaf margin doubly serrate | Leaf blades with margins with sharp teeth oriented toward the apex with each touth in turn with a smaller tooth. | |
| Leaf margin entire | Referring to leaf blade margins that are smooth, i.e., they have no serrations or crenations. |  |