The structure and development of mosses and ferns (Archegoniatae)

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Identifier: structuredevelop00camp3 (find matches)
Title: The structure and development of mosses and ferns (Archegoniatae)
Year: 1918 (1910s)
Authors: Campbell, Douglas Houghton, 1859-1953
Subjects:
Publisher: New York, Macmillan
Contributing Library: The LuEsther T Mertz Library, the New York Botanical Garden
Digitizing Sponsor: The LuEsther T Mertz Library, the New York Botanical Garden

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328 MOSSES AND FERNS CHAP. plant exceeds the leaves. In a plant with the fourth leaf stillunfolded, there were six fully-developed roots. The gaps in the vascular cylinder become more and moreprominent as the sporophyte develops, and there is finallyformed the wide-meshed reticulate cylinder found in the adultsporophyte. In some Ferns, e. g., Pteris aquilina, there are developedmedullary steles which arise from the inner surface of theprimitive stelar tube. (See Jeffrey (3), pp. 133, 134)-
Text Appearing After Image:
Fig. 181.—a, Vertical longitudinal section of the apex of a rhizome of Adiantumemarginatum, X2S; B, the central part of the same, Xi8o; L, a young leaf; C,cross-section of a similar stem apex, Xi8o; D, apex of a young leaf of Onocleastruthiopteris, showing the apical cell (jr). The Mature Sporophyte The Stem The stem in most of the Polypodiacese is either an erect orcreeping rhizome which, unlike that of the Eusporangiatae, oftenbranches freely. These branches are almost always formedmonopodlally, and are usually of the same structure as the mainaxis; but in O. struthiopteris great numbers of peculiar stolons IX FILICINE^ LEPTOSPORANGIAT^ 329 are formed that are quite different at first in appearance fromthe ordinary shoots. The main axis in this species is anupright rhizome about 2 cm. in diameter, but appearing muchlarger on account of the thick persistent leaf-bases which coverit. The stolons arise from the bases of these leaves, apparentlyas adventitious buds. They may remain do

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