. Morphology of gymnosperms. Gymnosperms; Plant morphology. CONIFERALES (TAXACEAE) 341 Ginkgo, but in Phyllocladus the nucleus (or nuclei) becomes free. As a consequence, the spores on the tip of the nucellus are found to contain three or four nuclei, one or two of which are vegetative, and the body cell. In Dacrydium (136) the generative cell is cut. Figs. 392-396.—Pollen grains of several podocarps: stalk, body, and prothaUial cells evident; fig. 392, Phyllocladus alpina, showing an evanescent and a persistent prothaUial cell, also stalk, body, and tube cells; X950; after Miss Yotjng (174);
. Morphology of gymnosperms. Gymnosperms; Plant morphology. CONIFERALES (TAXACEAE) 341 Ginkgo, but in Phyllocladus the nucleus (or nuclei) becomes free. As a consequence, the spores on the tip of the nucellus are found to contain three or four nuclei, one or two of which are vegetative, and the body cell. In Dacrydium (136) the generative cell is cut. Figs. 392-396.—Pollen grains of several podocarps: stalk, body, and prothaUial cells evident; fig. 392, Phyllocladus alpina, showing an evanescent and a persistent prothaUial cell, also stalk, body, and tube cells; X950; after Miss Yotjng (174); fig. 393, pollen grain of Microcachr-ys ietragona at the shedding stage; after Thomson (163); figs. 394, 395, Saxegothaea conspicua; fig. 394, the two prothaUial cells, the generative cell, and the tube cell are in a line; X700; after Noren (149); fig. 39S) later stage, showing body cell, and nuclei of tube, stalk, and three prothalUal ceUs; also several large starch grains; X700; afterT>J'0R:6N (149); &g. 3^6, Podocarpus tolarra Hallii; the usual condition of pollen grain at the shedding stage, containing tube nucleus, stalk and body cells, and eight prothaUial cells (only four shown) derived from the two primary prothalUal cells; after Biirlingame (139). off immediately after the two prothaUial cells, and then it and the second prothaUial cell divide. In some cases {D. Bidwillii) usually only the second prothaUial ceU divides, but in others (D. laxifoUum and D. cupressinum) both prothaUial ceUs divide. The result is that at pollination the spore contains three or four free vegetative nuclei, in addition to the body ceU and the stalk and tube nuclei. 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 Coulter, John Merle, 1851-1928; Chamberlain, Charles Joseph, b. 1863; Coulter, John Merle, 1851-1928.
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