. Carnegie Institution of Washington publication. Fig. 161. A. Section of adult rhizome of Danaa jamaicensis. B. Section of rhizome of D. elliptica. The mucilage ducts are not shown. THE ANATOMY OF THE LEAF. A section of the petiole of the adult leaf appears very much like a similar section of the stem, except that there is developed in the cortical region, separated by several rows of cells from the epidermis, a band of sclerenchyma, yellowish or brownish in color, and very much indeed like that common in the typical ferns. Holle's statement that a similar mantle of sclerenchyma o
. Carnegie Institution of Washington publication. Fig. 161. A. Section of adult rhizome of Danaa jamaicensis. B. Section of rhizome of D. elliptica. The mucilage ducts are not shown. THE ANATOMY OF THE LEAF. A section of the petiole of the adult leaf appears very much like a similar section of the stem, except that there is developed in the cortical region, separated by several rows of cells from the epidermis, a band of sclerenchyma, yellowish or brownish in color, and very much indeed like that common in the typical ferns. Holle's statement that a similar mantle of sclerenchyma occurs in the stem was shown to be an error, the result of his having investi- gated a fern which was not a Dan&a. There certainly was no trace of scleren- chyma in any of the specimens I have examined. The distribution of the vascular bun- dles in the petiole is very similar to that in Hclmtnthostachys, except that inside the ring of bundles there is a single larger centra] one, instead of the two small ones which occur in Helminthostachys. All the bundles are continued into the stem as separate strands or there may be a certain amount of anastomosing among them, as there is in Ophioglossum pendulum, which Datura resembles more in the character of its leaf traces than it does Helmin- thostachys, where the bundles of the petiole are united into a single trace within the cortex of the stem. The distribution of the mucilage ducts in the petiole is very much like that of the stem. There is a definite ring of these inside the zone of sclerenchyma and several larger ones in the central region, near the vascular bundles. The form and venation of the leaf is essentially the same as in the younger sporophytes which have already been described, and stomata are developed only upon the lower side, the epidermal cells showing a strongly undulate outline, except for the series of narrow cells which 12. Fig. 162.—Apex oi small root of Danaa Please note that these images are ex
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