File:The structure and development of the mosses and ferns (Archegoniatae) (1895) (14591461780).jpg

Identifier: structuredevelop00camp (find matches)
Title: The structure & development of the mosses and ferns (Archegoniatae)
Year: 1895 (1890s)
Authors: Campbell, Douglas Houghton, 1859-1953
Subjects:
Publisher: London, 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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anum. The tissues, especially thevascular bundles, are also more highly differentiated in thesespecies. Under favourable conditions well-grown plants of B. Vir-ginianum reach a height of 50 cm. or more, and the sterilelamina of the leaf, which is triangular in outline, may be30 to 40 cm. in breadth, and from three to four times pinnate.The texture of the leaf is membranaceous and not fleshy likethat of OpJiioglossum and most species of Botrychium. Thesporangiophore is twice or thrice pinnate. The plant sends upa single leaf each year from the underground stem, which isupright and several centimetres in length in old specimens.The roots are thick and fleshy, and much smaller at the pointof insertion. As in Ophioglossum each root corresponds prob-ably to a leaf, but the roots branch frequently, so that the rootsystem is much better developed than in Ophioglossum. Thesecondary roots of B. Virginianum arise laterally, and in muchthe same way as those of the higher Ferns. As in the terres-
Text Appearing After Image:
Fig. 122.—A, B, Botrychiuin simplex (Hitch), natural size; C, B. ternatiim (Sw.), Xg; D, leafsegment of i>. Iuna7-ia (Sw.) ; E, leaf segment of 5. Vifginianiiin (Sw.), natural size ; F, portionof sterile leaf segment oi Hcbninthostacliys Zcylanica (Hk.); G, fragment of the sporangiophoreof the same enlarged. A, B, C after Luerssen ; D, F after Hooker. R 242 MOSSES AND FERNS CHAP. trial species of Ophioglossuni, the development of the leaves isvery slow. In most species of Botrychium the relation of the leaf baseto the young bud and stem apex is the same as in OpJiioglossuin,except that the sheath is more obviously formed from the leafbase ; but in B. Vhginianuni the sheath is open on one side,and more resembles a pair of stipules. Fig. 123, A shows thestem and terminal bud of a plant of this species with all but B.

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