Displaying 41 - 80 out of 159 Object(s)
| Term | Definition | |
|---|---|---|
| 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. |  |
| Leaf margin erose | Referring to leaf blade margin that is jagged, i.e., uneven but not with well-defined teeth. | |
| Leaf margin lobed | Referring to rounded projections arising from the margins of a leaf blade that are cut less than one-half the distance to the midrib of the leaf blade, e.g., the leaves of the white oak group. | |
| Leaf margin serrate | Leaf blades with margins with sharp teeth oriented toward the apex. | |
| Leaf scar | The scar left on a stem when a leaf falls. |  |
| Leaf sheath | Tubular, inrolled base of a leaf blade or petiole that surrounds the node and a portion of the internode; e.g., in the Cyperaceae, Poaceae, and many other monocotyledons as well as in some dicotyledons. |  |
| Leaf symmetrical | Referring to the form of a leaf with the blade equal on each side of the midrib. | |
| Leaf symmetry | Referring to the form of a leaf in relation to the midrib, if the blade on each side of the midrib is equal the leaf is symmetrical and if the blades on each side of the midrib are not equal the leaf is asymmetrical. | |
| Leaf venation acrodromous | Referring to a type of leaf venation in which two or more primary or strongly developed secondary veins arch upward from either the base or above it; perfect acrodromous is used when these veins converge near the apex; e.g., Strychnos (Loganiaceae); imperfect acrodromous is used when these veins do not converge at the apex. Based on Hickey, 1973. For more information about leaf venation see Ellis et al, 2009. |  |
| Leaf venation actinodromous | Referring to a type of leaf venation in which three or more primary veins diverge radially from a single point either at (basal actinodromous) or above (suprabasal actinodrmous) the point of attachment of the petiole. The primary veins can either converge at the apex (perfect actinodromous) or not converge at the apex (imperfect actinodromous). Based on Hickey, 1973. For more information on leaf venation see Ellis et al., 2009. | |
| Leaf venation basal acrodromous | Referring to a type of leaf venation in which two or more primary or strongly developed secondary veins arch upward from the base and converge at or close to the apex.. Based on Hickey, 1973. For more information about leaf venation see Ellis et al, 2009. |  |
| Leaf venation basal actinodromous | Referring to a type of leaf venation in which three or more primary veins diverge radially from a single point at point of attachment of the petiole. | |
| Leaf venation brochidodromous | Referring to a type of leaf venation in which the secondary veins do not terminate at the margin but join to form a series of prominent arches that form a submarginal nerve; for example, in many Myrtaceae. Based on Hickey, 1973. For more information about leaf venation see Ellis et al, 2009. |  |
| Leaf venation brochidodromous festooned | Referring to a type of leaf venation in which the secondary veins do not terminate at the margin but join to form a series of prominent arches that form a submarginal nerve and, in addtion, the secondary veins possess closed loops toward their apices. Based on Hickey, 1973. For more information about leaf venation see Ellis et al, 2009. |  |
| Leaf venation camptodromous | Referring to a type of leaf venation in which the secondary veins do not terminate at the margin; in one type each secondary vein connects with the seconday vein above it (brochidodromous) and in the other type the secondary veins do not connect with the secondary vein above it (eucamtodromous). Based on Hickey, 1973. For more information about leaf venation see Ellis et al, 2009. | |
| Leaf venation campylodromous | Referring to a type of leaf venation in which a series of more or less equal primary veins originate from a common point at the base, arch upward, and reunite toward the apex; e.g., species of Aristolochia (Aristolochiaceae). |  |
| Leaf venation cladodromous | Referring to a type of leaf venation in which the secondary veins branch freely before they reach the margin. Based on Hickey, 1973. For more information about leaf venation see Ellis et al, 2009. |  |
| Leaf venation eucamptodromous | Referring to a type of leaf venation in which the secondary veins do not reach the margin and do not form a series of prominent arches. Based on Hickey, 1973. For more information about leaf venation see Ellis et al, 2009. |  |
| Leaf venation flabellate | Referring to leaf venation with several to many fine basal veins that spread out from the base like a fan and divide somewhat toward the apex. Based on Ellis et al., 2009. |  |
| Leaf venation hyphodromous | Referring to a leaf blade with all but the midvein absent or not visible because the leaf blade is too fleshy for them to be seen. |  |
| Leaf venation imperfect acrodromous | Referring to a type of leaf venation in which two or more primary or strongly developed secondary veins arch upward from or above the base and do not converge at the apex. Based on Hickey, 1973. For more information about leaf venation see Ellis et al, 2009. |  |