. Fundamentals of botany. Botany. 420 STRUCTURE AND LIFE HISTORIES that the ovuUferous scale represents two sporophylls fused together. 372. Megasporangia.^—As in Cycas, the megaspor- angium is an ovule, comprising a nucellus (sporangium proper), surrounded by an integument. At the apex the integument does not come quite together, so that a. Fig. 310.—Median longitudinal section of a pine cone, scale; 011, ovule at the base of a scale. , ovuliferous tiny opening or pore (the micropyle) is left. The micropyle leads to^the pollen-chamber below (Figs. 309 and 311). The megaspores are more back
. Fundamentals of botany. Botany. 420 STRUCTURE AND LIFE HISTORIES that the ovuUferous scale represents two sporophylls fused together. 372. Megasporangia.^—As in Cycas, the megaspor- angium is an ovule, comprising a nucellus (sporangium proper), surrounded by an integument. At the apex the integument does not come quite together, so that a. Fig. 310.—Median longitudinal section of a pine cone, scale; 011, ovule at the base of a scale. , ovuliferous tiny opening or pore (the micropyle) is left. The micropyle leads to^the pollen-chamber below (Figs. 309 and 311). The megaspores are more backward in development than the microspores, the spore-mother-cell not appearing until June. Reduction by two divisions gives rise to either three or four megaspores in a row, but only the basal one ever germinates; the others become disorganized and furnish nourishment for the one that 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 Gager, C. Stuart (Charles Stuart), 1872-1943. Philadelphia, P. Blakiston's son & co.
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Keywords: ., bookauthorgag, bookcentury1900, bookdecade1910, booksubjectbotany
