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CHAPTER XX.

PLATE XXXIV. —THE CAPsule, Pist11, stamINA, NigelLA, PLUMULE, AND RADICLE.

Fig. 1. The capsule or seed-vessel of the poppy: (papaver somniferum:) it is divided to exhibit its internal structure.

Fig. 2. Is an instance of an erect flower, the agave Americana; in which the pistil is shorter than the stamina. a, the pistil; b, the stigma; c, the stamina; d, the antherae.

Fig. 3. A flower of the crown-imperial. The relative length of the parts is now inverted. a, the pistil; b, the stamina.

Fig. 4. A blossom of the nigella.

Fig. 5. A grain of barley, showing the plumule and radicle growi"g from it.

CHAPTER XX.
PLATE XXXV.-vaLLisNERIA.

Fig. 1. Valisneria spiralis. The female plant, the flowers of which are purple. This is drawn from a specimen in the possession of Dr. Ogle.

Fig. 2. The male plant, producing white flowers; these when mature rise like air bubbles, and suddenly expanding when they reach the surface of the water, float about in such abundance as to cover it entirely. “Thus their pollen is scattered over the stigmas of the first mentioned blossoms, whose stalks soon afterwards resume their spiral figure, and the fruit comes to maturity at the botom of the water.”

Fig. 3. One of the separated male flowers magnified.

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