. Gray's school and field book of botany. Consisting of "Lessons in botany," and "Field, forest, and garden botany," bound in one volume. Botany; Botany. SECTION 9.] POLLEN. 103 293. By suppression lii certain cases the anther may be reduced to one cell or halved. In Globe Amaranth (Fig. 299) there is a single cell without vestige of any other. Different species of Sage and of the White Sages of California show various grades of abortion of one of the anther-cells, aloug with a singular lengthening of the connective (Fig. 303-305). 294. The splitting open of an anther for t
. Gray's school and field book of botany. Consisting of "Lessons in botany," and "Field, forest, and garden botany," bound in one volume. Botany; Botany. SECTION 9.] POLLEN. 103 293. By suppression lii certain cases the anther may be reduced to one cell or halved. In Globe Amaranth (Fig. 299) there is a single cell without vestige of any other. Different species of Sage and of the White Sages of California show various grades of abortion of one of the anther-cells, aloug with a singular lengthening of the connective (Fig. 303-305). 294. The splitting open of an anther for the discharge of its pollen is termed its Dehiscence. 295. As the figures show, this is commonly by a line along the whole length of each cell, either lateral or, when the anthers are extrorse, often along the outer face, and when introrse, along the inner face of each cell. Some- times the opening is only by a chink, hole, or pore at the top, as in the Azalea, Py- rola (Fig. 307), etc.; sometimes a part of tiie face separates as a sort of trap-door (or valve), hinged at the top, and open- ing to allow the escape of the pollen, as in the Sassafras, Spice-bush, and Barberry (Fig. 308). 296. Pollen. This is the powdery matter, commonly of a yellow color, which fills the cells of the anther, and is discharged during 309 310 311 312 313 after which the stamens generally fall or wither away. Under the micro- scope it is found to consist of grains, usually round or oval, and all aUke in the same species, but very different in different plants. So that the 811 316 316 317 818 plant may sometimes be recognized from the pollen alone. Several forms are shown in the accompanying figures. Fw. 306. Stamen with the usual dehiscence of antlier down the side of each cell. Fig. 307. Stamen of Pyrola; cells opening ty a terminal hole. FlQ. 308. Stamen of Barberry; cells of anther each opening by an uplifted valve. Fig. 809. Magnified pollen of a Lily, smooth and oval; 310, of Eohinoc
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