The structure & development of the mosses and ferns (Archegoniatae) . Fig. 178.—A, Horizontal section of an advanced embrjo of O. Claytoniana, passing through thecotyledon and foot, X 230; B, longitudinal section of the stem apex in a somewhat older embryoof O. cinnamoiiica, X 460; C, transverse section of the apex of the primarj root of the same,X460. could not be positively shown whether or not it was afterwardsreplaced by a two-sided one. The further development of the. Fig. 179.—Transverse section of a prothallium of O. Claytoniana, showing the lateral position of the embrjo (e7n\ x 75. co
The structure & development of the mosses and ferns (Archegoniatae) . Fig. 178.—A, Horizontal section of an advanced embrjo of O. Claytoniana, passing through thecotyledon and foot, X 230; B, longitudinal section of the stem apex in a somewhat older embryoof O. cinnamoiiica, X 460; C, transverse section of the apex of the primarj root of the same,X460. could not be positively shown whether or not it was afterwardsreplaced by a two-sided one. The further development of the. Fig. 179.—Transverse section of a prothallium of O. Claytoniana, showing the lateral position of the embrjo (e7n\ x 75. cotyledon corresponds almost exactly with Onoclea. It doesnot break through the calyptra until later, and in this respect XI THE HOMOSPOROUS LEPTOSPORANGIATAl 351 shows its primitive character. The sini^lc vascular bundle ofthe petiole approaches the collateral type, and is much likethat of the cotyledon of Marattia. Stomata of the usual formoccur on both sides of the lamina. The development f;f thestem offers no peculiarities. The apical cell is of the tctra-hedral form found in the mature sporophyte. The root is bulky, and the apical cell relatively small, withlarge segments, dividing less regularly than in Onodea, and onthe whole approaches most nearly to Botrychium. The formof the apical cell is like that of Onodea or Botrydiium, and isinteresting because in the later roots this is replaced by anotherform, so that this would indicate that the three-sided formfo
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Keywords: ., bookcentury1800, bookdecade1890, bookidstructuredev, bookyear1895
