File:The structure and development of mosses and ferns (Archegoniatae) (1918) (14762136776).jpg

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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system is muchbetter developed than in Ophioglossuin. The secondary rootsof B. Viro-inianuiu arise laterallv, and in much the same way asthose of the higher Ferns. As in the terrestrial species ofOphioglossnm, the development of the leaves is very slow. In most species of Botrychium the relation of the leaf baseto the young bud and stem apex is the same as in Ophioglossnm,except that the sheath is more obviously formed from the leafbase; but in B. Virginianum the sheath is open on one side, andmore resembles a pair of stipules. Fig. 142, A shows the stemand terminal bud of a plant of this species with all but the baseof the leaf of the present year cut away, and B the same with thebud cut open longitudinally. At this stage the parts of theleaf for the next year are well advanced, and the formation ofthe individual sporangia just begim. The leaf for the secondyear already shows the sporangiophore clearly evident, and theleaf which is to unfold in three years is evident, but the sporan-
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Fig. 141.—A, B, Botrychium simplex, slightly enlarged; C, B. ternatum, X % 5 D, leafsegment of B. lunaria; E, leaf segment of B. Virginianum, natural size; F, portionof sterile leaf segment of Helminthostachys Zeylanica; G, fragment of the sporan-giophore of the same enlarged. A, B, C after Luerssen; D, F after Hooker. VII P TERIDOPH Y TA—FILICINE/E—0 PIIIOGLOSSA CEAB 261 giophore not yet differentiated. At the base of the youngestleaf is the stem apex. The wliole bnd is covered in this specieswith numerous short hairs, which are also found in B. tcrnatumand some other species; but in B. simplex and the other simplerspecies it is perfectly smooth, as in Ophiof^lossuiii. The youngleaves in B. Virginianuni are bent over, and the segments of theleaf are bent inward in a way that recalls the vernation of thetrue Ferns. The sporangiophore grows out frrjin the innersurface of the lamina, and its branches are directed in theopposite direction from those of the sterile part of the leaf.

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