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Reticulate venation seems to have appeared at least 26 times in monocots, and fleshy fruits have appeared 21 times (sometimes lost later); the two characteristics, though different, showed strong signs of a tendency to be good or bad in tandem, a phenomenon described as "concerted convergence" ("coordinated convergence"). [133] [134]
A pseudo-reticulate venation that is actually a highly modified penniparallel one is an autapomorphy of some Melanthiaceae, which are monocots; e.g., Paris quadrifolia (True-lover's Knot). In leaves with reticulate venation, veins form a scaffolding matrix imparting mechanical rigidity to leaves. [34]
Reticulate venation occurs in dicots, [4] where the primary vein branches into a network; parallel venation is found in monocots, where multiple veins run parallel to each other. [ 5 ] References
Glossopteris should strictly be used to refer to the distinctive spathulate fossil leaves with reticulate venation, however, the term has also been used to refer to the parent plant as a whole. [37] Leaves of Glossopteris are associated with reproductive structures belonging to the family Dictyopteridiaceae within the Glossopteridales. [38]
(of leaf venation) Palmate or radially arranged venation with three or more primary vein s arising at or near the base of the leaf and reaching the margin in most species, but not all. actinomorphic Regular or radially symmetrical; [12] may be bisected into similar halves in at least two planes.
Members of this family can be herbaceous to "woody" vines. 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.
It is a monocot with reticulate venation. The midrib of the underside of the leaf is also provided with spines. The flowers, very fragrant, are small, yellowish or greenish, gathered in axillary racemes. The flowering period in Mediterranean regions extends from September to November.
The leaves are in pairs or whorls of three, thick and leathery, dark-green, narrow lanceolate, 5–21 centimetres (2–8 inches) long and 1–3.5 cm (3 ⁄ 8 – 1 + 3 ⁄ 8 in) broad, and with an entire margin filled with minute reticulate venation web typical of eudicots. The leaves are light green and very glossy when young, maturing to a ...