. Studies in fossil botany . Paleobotany. MEDULLOSEAE 427 In some cases, pinnae of a different form, without a median nerve, and described under the name of Cyclopteris, were attached directly to the rachis, and may have been of a stipellar nature. These organs are of the same kind as the " Aphlebiae," mentioned in Chapter VIII. as occurring on the fronds of Ferns. In the genus Aletlw- pteris the leaves are likewise large, and bi- to tripinnate, but here the thick, usually oblong pinnules are inserted on the rachis by a broad, decurrent base, and are in some cases confluent with one
. Studies in fossil botany . Paleobotany. MEDULLOSEAE 427 In some cases, pinnae of a different form, without a median nerve, and described under the name of Cyclopteris, were attached directly to the rachis, and may have been of a stipellar nature. These organs are of the same kind as the " Aphlebiae," mentioned in Chapter VIII. as occurring on the fronds of Ferns. In the genus Aletlw- pteris the leaves are likewise large, and bi- to tripinnate, but here the thick, usually oblong pinnules are inserted on the rachis by a broad, decurrent base, and are in some cases confluent with one another. The edges of each leaflet are incurved on the lower side. The median nerve extends the whole length of the pinnule, and is prominent on its under surface ; the secondary nerves leave the median one at a wide angle, and pass directly, with or without dichotomy, to the margin (see Fig. 162). The habit resembles that of the recent Marattiaceous Fern A ngiopteris. In the case of both these so-called genera, founded on the external characters of the leaf, there is now good evidence that they belonged to stems of the family Medulloseae, of which the structural characters. Fig. 162.—Alcthopteris lonchitica (foliage of a Mcdullosa). Part of frond. Reduced. From a photograph by Mr. W. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Scott, Dukinfield Henry, 1854-1934. London, A. and C. Black
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