. Class-book of botany : being outlines of the structure, physiology, and classification of plants ; with a flora of the United States and Canada . Botany; Botany; Botany. THE STAMENS, OR ANDHKCIUM. 103 phous, many sets, as in St. John'swort; and syngenesious, when they are united by their anthers, as in the Compositaj. Finally, 507. The absence of the stamens altogether, whether by abortion, as in the $ flowers of Veratrum, or by suppression, as in oak, occurs in various modes, rendering the plant monoecious (§ ), dioecious ( (3 ? ), or polygamous ( ,S ^ 9 ), as already explained (§ 421). 508
. Class-book of botany : being outlines of the structure, physiology, and classification of plants ; with a flora of the United States and Canada . Botany; Botany; Botany. THE STAMENS, OR ANDHKCIUM. 103 phous, many sets, as in St. John'swort; and syngenesious, when they are united by their anthers, as in the Compositaj. Finally, 507. The absence of the stamens altogether, whether by abortion, as in the $ flowers of Veratrum, or by suppression, as in oak, occurs in various modes, rendering the plant monoecious (§ ), dioecious ( (3 ? ), or polygamous ( ,S ^ 9 ), as already explained (§ 421). 508. The pollen is in appearance a small, yellow dust, contained in the cells of the anther. When viewed with the microscope it appears as grains of various forms, usually spheroidal, or oval, sometimes tri- angular or polyhedral, but always of the same form and appearance in the same species. Externally they are curiously, and often elegantly figured with stripes, bands, dots, checks, etc. 8T1. Pollen grains. 867, Finns larico. 363, Basella rubra. 869, Eanunoulus repena. mufl grandiHorus. 871, Passiflora incarnata. 509. Each grain of pollen is a mem- branous cell or sack containing a fluid. Its coat is double, the outer is more thick and firm, exhibiting one or more breaks where the inner coat, which is very thin and expansible, is uncovered. In the fluid are suspended molecules of inconceivable minute- ), said to possess a tre- mulous motion. When the membrane is exposed to moisture it swells and bursts, discharging its contents. 510. POLLINIA. In the Orchids and Silkweed. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Wood, Alphonso, 1810-1881. New York : A. S. Barnes & Burr
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