. Nature and development of plants. Botany. 38o SPOROPHYLLS OF ANGIOSPERMS rangia in which the microspores originate in fours as in the preceding groups (Fig. 261A, 3, 4). At maturity, the two sporangia on each side of the anther usually merge into one cavity, owing to the breaking down of the intervening tissue. The anther opens in a variety of ways, as by slits and pores, permitting the scattering of the spores (Fig. 261 A, 3). The. Fig. 2615. Megasporophyll and megasporangium: i, megasporophyll of buttercup—s, stigma; st, style; 0, ovary. 2, longitudinal section of mega- sporophyll—mg, mega
. Nature and development of plants. Botany. 38o SPOROPHYLLS OF ANGIOSPERMS rangia in which the microspores originate in fours as in the preceding groups (Fig. 261A, 3, 4). At maturity, the two sporangia on each side of the anther usually merge into one cavity, owing to the breaking down of the intervening tissue. The anther opens in a variety of ways, as by slits and pores, permitting the scattering of the spores (Fig. 261 A, 3). The. Fig. 2615. Megasporophyll and megasporangium: i, megasporophyll of buttercup—s, stigma; st, style; 0, ovary. 2, longitudinal section of mega- sporophyll—mg, megasporangium; m, megaspore, the mother cell having formed four spores in series, but the end one only develops; i, integument; mi, micropyle. microsporophylls are often externally quite suggestive of those noted in certain of the Pinales, but the megasporophylls are essentially different from any other group considered, in that the sporangia are inclosed in a cavity formed in the sporophyll. This peculiarity is one of the important characteristics of the angiosperms, as the name indicates. The megasporophyll, often termed the pistil or carpel, is usually a rather elongated, flask- shaped organ with a hollow swollen base and consists of a stigma, style and ovary (Fig. 2615, i) within which are produced the megasporangia or ovules. Such a structure would result if the edges of the leaf-like megasporophylls of previous groups were inrolled so as to form a closed organ. The megaspores originate. 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 Curtis, Carlton Clarence, 1864-1945. New York, H. Holt
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