Placentation parietal

Leaves often small placentation parietal stamens mostly definite.Order Tamaricales... 

Placentation Parietal The condition in which the ovules are attached to the outer wall of the ovary of plants. 

Submerged freshwater apetalous herbs like mosses, hepatics, or algae syncarpous with parietal or central placentation... 

Trees or shrubs stipules mostly present placentation axile or parietal stamens many to few. .Order Cunoniales... 

Compound Pistils are composed of carpels which have united to form them, and therefore their ovaries will usually have just as many cells (locules)- as carpels. When each simple ovary has its placenta, or seed-bearing tissue, at the inner angle, the resulting compound ovary has as many axile or central placente as there are carpels, but all more or less consolidated into one. The partitions are called dissepiments and form part of the walls of the ovary. If, however, the carpels are joined by their edges, like the petals of a gamopetalous corolla, there will be but one cell, and the placenta will be parietal, or on the wall of the compound ovary. 

The Placenta.—The placenta is the nutritive tissue connecting the ovules with the wall of the ovary. The various types of placenta arrangement (placentation) are gouped according to their relative complexity as follows (i) Basilar, (2) Sutural, (3) Parietal, (4) Central, (5) Free Central. 

Parietal placentation is seen in Gloxinia, Gesneria, Papaver, etc. Here we find two or more carpels joined and placental tissue running up along edges of the fused carpels bearing the ovules. 

Central or axile placentation is seen in Campanulacece (Lobelia), where the two, three, or more carpels have folded inward until they meet in the center and in the process have carried the originally parietal placenta with them. This then may form a central swelling bearing the ovules over the surface. 

Flowers of catkins numerous, each of two to five (Willow) or six to fifteen (Poplar) stamens in axil of a small bract leaf, sometimes with small nectar knob or girdle at base pollen abundant, hence plants anemophUous, rarely entomophilous. Pistillate flowers green, each of a bicarpellate pistil in axil of bract, ovary one-celled with parietal placentation, style simple, stigma bilobed. 

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