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The primary leaf or leaves of a plant embryo which upon germination develops into the seed-leaf or the first set of leaves. craspedodromous Pinnate venation in which the secondary veins terminate at the margin s, often as teeth. crateriform In the shape of a saucer or shallow cup; hemispherical or more shallow. cremnophyte
The ovate-elliptical leaf blade is uniformly green, [4] and it can reach up to 18 cm in length and 14 cm in width. [5] The leaf venation is reticulate and dichotomous, with 9-15 primary veins. [3] The leaf blade is attached to glabrous, max. 4 mm wide petioles with 2-4 primary and 4-6 secondary air canals. [5]
Leaf of Pyrus calleryana with petiole. In botany, the petiole (/ ˈ p iː t i. oʊ l /) is the stalk that attaches the leaf blade to the stem. [1]: 87 [2]: 171 It is able to twist the leaf to face the sun, producing a characteristic foliage arrangement (spacing of blades), and also optimizing its exposure to sunlight.
Having leaf tissue taper down the petiole to a narrow base and always having some leaf material on each side of the petiole auriculate: auriculatus: leaf base: Having ear-shaped appendages reaching beyond the attachment to the petiole or stem (in case of a seated leaf) caudate: caudatus: leaf tip: Tailed at the apex cirrus, cirrate: leaf tip
Less commonly, dicot leaf blades may have palmate venation (several large veins diverging from petiole to leaf edges). Finally, some exhibit parallel venation. [19] Monocot leaves in temperate climates usually have narrow blades and usually parallel venation converging at leaf tips or edges. Some also have pinnate venation.
Leaf shape oblong or linear, often sheathed at base, petiole seldom developed, stipules absent. Major leaf veins usually parallel: Broad, seldom sheathed, petiole common often with stipules. Veins usually reticulate (pinnate or palmate) Roots: Primary root of short duration, replaced by adventitial roots forming fibrous or fleshy root systems
They grow from their rhizomes and are often armed with prickles on the stems and/or leaves. Leaves are alternate and simple; and entire to spinose-serrate. Some members of this family have coriaceous (leathery) leaves. Venation of the leaves may be palmate to reticulate. A pair of tendrils often appear near the base of the petiole.
Mature sun leaves may be 33 cm (13 in) long and 14 cm (5.5 in) wide, shade leaves are smaller. They are coriaceous, obovate to broadly elliptic in shape, and are held on petioles that may be up to 25 mm (1 in) long. They have 6–10 pairs of secondary veins that depart from the midrib at an angle between 55–65°, and reticulate tertiary venation.