. The structure and development of mosses and ferns (Archegoniatae). Fig. 179.—Onoclea struthiopteris. A, Longitudinal section of young sporophyte stillconnected with the prothallium (Pr), X6o; B, the apex of same, Xi8o; C, surfaceview of the young cotyledon showing the first dichotomy; D, central region of A,showing the primary tracheary tissue, Xi8o; E, young sporophyte with nearlyfull-grown cotyledon and primary root, X3; st, stem; L^, cotyledon; L^ secondleaf; F, foot; Pr, prothallium. the prothallium. As in Marattia the growth is much strongerupon the outer side and the leaf is strongly c
. The structure and development of mosses and ferns (Archegoniatae). Fig. 179.—Onoclea struthiopteris. A, Longitudinal section of young sporophyte stillconnected with the prothallium (Pr), X6o; B, the apex of same, Xi8o; C, surfaceview of the young cotyledon showing the first dichotomy; D, central region of A,showing the primary tracheary tissue, Xi8o; E, young sporophyte with nearlyfull-grown cotyledon and primary root, X3; st, stem; L^, cotyledon; L^ secondleaf; F, foot; Pr, prothallium. the prothallium. As in Marattia the growth is much strongerupon the outer side and the leaf is strongly curved over. Itvery early grows beyond the stem apex, and the embryo loses itsoval form much earlier than is the case with any of theEusporangiatse. The Stem The early segmentation of the stem apex is much the sameas in the cotyledon; but later the divisions in the segments aresomewhat different, and the first wall is a radial one, instead of ^ FILICINEJE LEPTOSrORANGIATAi 325 periclinal. The stem is very short at the time the young-sporophyte breaks through the
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Keywords: ., bookauthorcampbelldouglashought, bookcentury1900, bookdecade1910
