. Fossil plants : for students of botany and geology . Paleobotany. 468 BBNNETTITALBS [CH. similar to those of Williamsonia: this portion is 6 mm. in diameter and 1 cm. long. A whorl of separate cuneate microsporophylls forms a hypogynous ring below the basal interseminal scales: each sporophyll is attached by a narrow base (fig. 570) and bears 5â6 renifomi synangia containing microspores. The flower is thus bisexual: it affords no conclusive evidence of the occurrence of any covering bracts like those of most Bennettitalean flowers. In young specimens the microsporophylls are closely packed.
. Fossil plants : for students of botany and geology . Paleobotany. 468 BBNNETTITALBS [CH. similar to those of Williamsonia: this portion is 6 mm. in diameter and 1 cm. long. A whorl of separate cuneate microsporophylls forms a hypogynous ring below the basal interseminal scales: each sporophyll is attached by a narrow base (fig. 570) and bears 5â6 renifomi synangia containing microspores. The flower is thus bisexual: it affords no conclusive evidence of the occurrence of any covering bracts like those of most Bennettitalean flowers. In young specimens the microsporophylls are closely packed. Fig. 570. Williamsoniella coronaia. Dia- grammatic sketch of a mierosporophyl] in section and in side-view. (After Thomas; x 3.) Fig. 569. Williamsoniella coronata. Vertical section of the flower showing the pyriform axis with small megasporophyUs and inter- seminal scales and the microsporo- phylls with synangia. (After Thomas; x 2.) round the axis (fig. 571, B). The flower-stalks reach a length of 3-5 cm. and are 3 mm. in diameter. Fig. 571, C, shows a receptacle from which the sporophylls have fallen: the microsporophylls having been no doubt attached to the collar-like swelling at the base. Towards the apex the axis becomes broader and at *â a few interseminal scales are left: above these is the apical disc (corona) characterised by longitudinal ribs. An apical disc is. 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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Keywords: ., bookcentury1800, bookdecade1890, bookpublishercambr, bookyear1898
