. Morphology of spermatophytes. [Part I. Gymnosperms]. Gymnosperms; Plant morphology. 132 MORPHOLOGY OF SPERMATOPHYTBS. In the germination of the oospore, and in the structure of the female gametophyte, there is evidence that Tumhoa and Gnetum are allied forms, the latter hav- ing proceeded further in the reduction of its gametophyte preceding fertiliza- tion. It is also evident that Ephedra must be associated with them as the least modified form, its gametophyte retain- ing the character of those in other Gym- nosperms, while the germination of its oospore is fairly transitional between Conif
. Morphology of spermatophytes. [Part I. Gymnosperms]. Gymnosperms; Plant morphology. 132 MORPHOLOGY OF SPERMATOPHYTBS. In the germination of the oospore, and in the structure of the female gametophyte, there is evidence that Tumhoa and Gnetum are allied forms, the latter hav- ing proceeded further in the reduction of its gametophyte preceding fertiliza- tion. It is also evident that Ephedra must be associated with them as the least modified form, its gametophyte retain- ing the character of those in other Gym- nosperms, while the germination of its oospore is fairly transitional between Conifers on the one hand and Tumhoa, and Gnetum on the other. There is free nuclear division in the oospore, as in Conifers, biit the cells organized in con- nection with them remain independent and behave as do the oospores of Tumhoa and Gnetum. It should be remarked, also, that the number of free cells de- veloped within the oospore of Ephe- dra may be reduced to two, and that any further reduction would probably result in causing the whole oospore to behave as do these of Tumhoa and Gnetum. If Ephedra be associated with Tumhoa and Gnetum,, as seems reasonable, there is equally weighty evidence for regarding it as the group of Gnetales most nearly related to the Conifers, for its female gametophyte and the early stages in the germination of its oospore are identical with those in Conifers. Fig. 93.—Gnetum Gnemon: A^ ix young embryo at the tip of a snspensor and im- bedded in endosperm; B, a germinating seed, the root and stem tips having escaped, and the foot re- maining within the seed coat.—After Bowek. LITEEATUEE CITED 1. Hooker, J. D. On Welwitschia, a new genus of Gnetaceae. Trans. Linn. Soc. London 24: 1-48. pis. 1-U. 1863. 2. EiCHLER, A. W. Ueber Welwitschia mirabilis, etc. Flora 47: 459-464, 473-479, 4S9-496, 508-510, 513-520. 1863. 3. Strasburger, E. Die Coniferen und die G-netaceen. 1872. 4. Bbccari, O. Delia organogenia dei flori feminei del Gnetum Gnemon "L. N
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