. Fossil plants : for students of botany and geology . Paleobotany. xxxvn] WILLIAMSONIA 437 discovered by Prof. Nathorst in the Lower Estuarine series of Wlutby; it has also been obtained from beds of the same age at Marske in the Cleveland district of Yorkshire^- WilUamsonia spectabilis, though indubitably a male organ, has not been found attached to a stem, and there is no decisive evidence as to its connexion with a particular species of frond. Nathorst beUeves that it belongs to the plant which bore the leaves known as. Fig. 551. Williamsonia spectabilis and leaves of Ptilophyllum pecten.
. Fossil plants : for students of botany and geology . Paleobotany. xxxvn] WILLIAMSONIA 437 discovered by Prof. Nathorst in the Lower Estuarine series of Wlutby; it has also been obtained from beds of the same age at Marske in the Cleveland district of Yorkshire^- WilUamsonia spectabilis, though indubitably a male organ, has not been found attached to a stem, and there is no decisive evidence as to its connexion with a particular species of frond. Nathorst beUeves that it belongs to the plant which bore the leaves known as. Fig. 551. Williamsonia spectabilis and leaves of Ptilophyllum pecten. (Aftep Nathorst; f nat. size.) Ptilophyllum pecten, an opinion based chiefly on association. The more complete specimens consist of a broad funnel-shaped organ prolonged below into a slender stalk and divided at the margin into several hnear-lanceolate segments (microsporophyUs) the apices of which were roUed inwards like young fern-fronds (figs. 551, 552). The synan^a agree closely in form and in such structural features as can be made out from cuticular preparations with those described by Wieland in American species of Cyca- deoidea; they are sHghtly reniform, 5—6 mm. long and 2 mm. broad and divided into several locuh by transverse partitions 1 Thomas (13^) p. 230, PI. xxiv. figs. 1— 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 Seward, A. C. (Albert Charles), 1863-1941. Cambridge : University Press
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