File:The structure and development of mosses and ferns (Archegoniatae) (1918) (14784771832).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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n tropics, may be taken as a type of the sim-plest of the Ophioglossacese. Its short creeping stem growsupon the trunks of trees, especially tree-ferns, from which thelong flaccid leaves hang down. The lamina of the leaf mergesinsensibly into the stout petiole whose fleshy base forms a sheathabout the next younger leaf. Corresponding to each leaf is athick unbranched root, which penetrates into the crevices ofthe bark and holds the plant secure. These roots are smooth,and show no trace of rhizoids. The petiole is continued up intothe lamina as a very broad and thick midrib, which in the spo-riferous leaves (sporophylls) is continued into the peculiarelongated spike which bears the sporangia. The petiole if cut across shows a number of vascular bundlesarranged in a single row, nearly concentric with the peripheryof the section. As these enter the lamina they anastomose andform a network with elongated meshes (Fig. 133, C) and nofree ends. Sections of the spike cut parallel to its broad
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Fig. 13:.—Ophioglossiim pendulum. A, Leaf with sporangiophore, natrual size; B,cross-section of the petiole, X6; C, section of the sporangiophore, parallel to ttsbroad surface, X6. VII PTERIDOPHYTA—FILICINEJE—OPHIOGLOSSACE^ 24.7 diameter show a somewhat similar arran<^rement of the vascularbundles, but here there are free brandies exteiKhng between thesporangia. The relations of the bundles of the fertile and sterileparts of the leaf are bestfollowed in the smallerspecies. Prantl ((7), p.155) describes it as fol-lows for O. Liisitanicum,and states that it is essen-tially the same in otherspecies. The primarybundle given off from thestem branches just after itenters the petiole. Themain bundle gives off twosmaller lateral branchesright and left. The latterbranch again near the baseof the sporangiophore,andthe upper branches fromeach unite to form the sin-gle bundle that enters thelatter. The sporangia aresunk in the tissue of thesporophyll, and scarcelyproject at all above the

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