. Pharmaceutical botany. Botany; Botany, Medical. 54 PHARMACEUTICAL BOTANY ^E A. Fig. 31.—Section o£ a grain of wheat. A, Pericarps and seed coats; B, layer of cells in endosperm containing aleurone grains; C, cells of the endosperm containing starch grains. (From Hamaker.) seminated by wind currents. Examples of these are seen in the Milk- weed, which has a tuft of hairs at one end of the seed called a Coma, and in the official Strophanthus, which has a long bristle-like appendage attached to one end of the seed and called an awn. The wart-like appendage at the hilum or micropyle, as in Casto
. Pharmaceutical botany. Botany; Botany, Medical. 54 PHARMACEUTICAL BOTANY ^E A. Fig. 31.—Section o£ a grain of wheat. A, Pericarps and seed coats; B, layer of cells in endosperm containing aleurone grains; C, cells of the endosperm containing starch grains. (From Hamaker.) seminated by wind currents. Examples of these are seen in the Milk- weed, which has a tuft of hairs at one end of the seed called a Coma, and in the official Strophanthus, which has a long bristle-like appendage attached to one end of the seed and called an awn. The wart-like appendage at the hilum or micropyle, as in Castor Oil Seed, is called the Caruncle. The tegmen or inner coat surrounds the nucellus closely and is generally soft and delicate. A third integument, or accessory seed covering, is occasionally present and is called the Aril. Ex.: Euonymus (suc- culent). When such an integument arises at the micropyle of the seed, as in the Nutmeg, it is known as an arUlode. The Nucellus or Kernel consists of tissue containing albumen, when this sub- stance is present, and the embryo. Albu- men is the name given the nutritive matter stored in the seed. MODE OF FORMATION OF DIFFERENT TYPES OF ALBUMEN If the egg cell within the embryo sac segments and grows into the embryo and, stretching, fills up the cavity without food mate- rial laid down around it, it happens that the nutritive material lin- gers in the cells of the nucellus pressing around the embryo. This is called Perispermic Albumen. Seen in the Polygonaceas. In by far the greater number of Angiosperms, the endosperm nu- cleus, after double fertilization, divides and redivides, giving rise to numerous nuclei imbedded in the protoplasm of the embryo sac out- side of the developing embryo. Gathering protoplasm about them- selves and laying down cell walls they form the endosperm tissue outside of the embryo. Into this tissue food is passed constituting the^Endospermic albumen. In the Marantaceae, Piperacese, etc., nutritive material is pa
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