. Fossil plants : for students of botany and geology . Paleobotany. XXXVIl] WILLIAMSONIA 439 of the lower part of the cup to break away from the coherent bases of the sporophylls (fig. 551)i, and it is not unlikely that some of the impressions described as infundibuliform appendages are incomplete examples of Williamsonia spectabilis. WilUamsonia Leckenbyi Nathorst. This species, founded on specimens from the Middle Estuarine beds exposed on the Yorkshire coast at Cloughton Wyke^, is characterised by the almost spherical form of the strobilus, ^•5—5 cm. in diameter. The relatively small recept
. Fossil plants : for students of botany and geology . Paleobotany. XXXVIl] WILLIAMSONIA 439 of the lower part of the cup to break away from the coherent bases of the sporophylls (fig. 551)i, and it is not unlikely that some of the impressions described as infundibuliform appendages are incomplete examples of Williamsonia spectabilis. WilUamsonia Leckenbyi Nathorst. This species, founded on specimens from the Middle Estuarine beds exposed on the Yorkshire coast at Cloughton Wyke^, is characterised by the almost spherical form of the strobilus, ^•5—5 cm. in diameter. The relatively small receptacle is covered by a thick mass of megasporophylls and interseminal scales except in the lower part which bears only sterile scales. Nathorst believes that the seeds were very small, but no undoubted examples have been found. A specimen in the British Museum, figured m 1900', shows the surface-view of an impression of the base of. Fig. 553. Williamsonia Leckenbyi. Surface-view and in section. (Restoration after Nathorat.) the flower; a small circular raised boss occupies the centre— the scar of the receptacle—and surrounding this is a reticulum formed by the impression of the distal ends of the interseminal scales. TJie uniform nature of the reticulum, the meshes of which are all of the same type, shows that in the basal region of the flower the organs borne on the receptacle were all sterile as in Cycadeoidea (Bennettites) Morierei. Except in the smaller diameter of the receptacle this specimen is practically identical with that of Williamsonia Carruthersi Sew. reproduced in fig. 559. The form of the strobilus is shown in Nathorst's restoration* represented in fig. 553. The interseminal scales have broad peltate 1 Nathorst (09) PI. i. figs. 1—3. 2 Ibid. (80) p. 39. See also Saporta (91) p. 161, PI. 248. ' Seward (00) B. p. 201, fig. 35. * Nathorst (09) p. 14, Pis. n., Please note that these images are extracted from scanned page images that may have been digitall
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