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Leaf base cordate
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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. |
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Leaf base cuneate
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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°. |
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Leaf base decurrent
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Referring to a leaf blade base that extends down the petiole. |
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Leaf base lobate (lobed)
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A rounded projection arising from the base of a leaf blade. |
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Leaf base obtuse
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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°. |
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Leaf base rounded
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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. |
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Leaf base sagittate
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The base of a leaf blade shaped like an arrowhead. |
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Leaf base truncate
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Referring to the base of a leaf blade that terminates abruptly in a nearly straight horizontal edge. |
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Leaf blade
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The expanded portion of a leaf, it and the petiole combined equal the leaf. Same as lamina. |
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Leaf flush
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The expansion of new leaves. |
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Leaf flush
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The expansion of new leaves. |
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Leaf gap
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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. |
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Leaf margin crenate
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Referring to a leaf blade margin with teeth rounded at the apex. Compare with serrate. |
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Leaf margin dentate
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Referring to a leaf margin with sharp teeth oriented at right angles to the central axis of the leaf blade. |
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Leaf margin doubly serrate
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Leaf blades with margins with sharp teeth oriented toward the apex with each touth in turn with a smaller tooth. |
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Leaf margin entire
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Referring to leaf blade margins that are smooth, i.e., they have no serrations or crenations. |
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Leaf margin erose
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Referring to leaf blade margin that is jagged, i.e., uneven but not with well-defined teeth. |
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Leaf margin lobed
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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. |
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Leaf margin serrate
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Leaf blades with margins with sharp teeth oriented toward the apex. |
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Leaf opposed
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Referring to an inflorescence, infructescence, or tendril arising from the stem opposite a leaf. |
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Leaf scar
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The scar left on a stem when a leaf falls. |
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Leaf sheath
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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. |
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Leaf symmetrical
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Referring to the form of a leaf with the blade equal on each side of the midrib. |
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Leaf symmetry
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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. |
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Leaf venation acrodromous
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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. |
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