. A textbook of botany for colleges and universities ... Botany. 222 MORPHOLOGY the stamen is peltate (as in taxads), and one-sided peltate (as in Tor- reya). The sporangia are developed as usual, and in the Abietineae the pollen grains (microspores) are winged (as in podocarps, fig. 489). Ovulate strobilus. —The ovulate strobilus of Pinaceae has been the subject of much discussion. In the Abietineae the strobilus is made up of a series of bracts, in the axil of each of which a so-called ovulif- erous scale appears, which usually bears two ovules whose micropyles are directed towards the base
. A textbook of botany for colleges and universities ... Botany. 222 MORPHOLOGY the stamen is peltate (as in taxads), and one-sided peltate (as in Tor- reya). The sporangia are developed as usual, and in the Abietineae the pollen grains (microspores) are winged (as in podocarps, fig. 489). Ovulate strobilus. —The ovulate strobilus of Pinaceae has been the subject of much discussion. In the Abietineae the strobilus is made up of a series of bracts, in the axil of each of which a so-called ovulif- erous scale appears, which usually bears two ovules whose micropyles are directed towards the base of the scale (fig. 490). In the other tribes the bract and ovuliferous scale are more or less united. The discussion. Figs. 491, 492. — Archegonium complex of Thuja: 491, group of archegonium initials; 492, two mature archegonia (reached by a pollen tube, in which the body cell has not yet divided) with a common archegonial chamber and a common archegonial (nutritive) jacket. — After Land. referred to has to do with the nature of the ovuliferous scale, and many facts indicate that it represents a fused pair of leaves of a dwarf axillary branch. This means that the ovules are borne in the strobilus on axes of the second order, as in Cordaitales, and that the ovulate strobilus of Pinaceae is a compound strobilus. Ovule.—The structure of the ovule is as described for Taxaceae, except that the outer fleshy layer does not develop, and the seed is dry ; that both sets of vascular strands have been eliminated; and also that there is the same elaborate nutritive mechanism that was described for Ginkgo. The development of the ovule and the seed is usually. 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; Barnes, Charles Reid, 1858-1910, joint author; Cowles, Henry Chandler, 1869
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1910
