. Fossil plants : for students of botany and geology . Paleobotany. 414 PSARONIEAE [CH, is applied to steins exhibiting spirally disposed leaf-scars like those of recent tree-ferns; in Megaphyton the scars are dis- tichously arranged, in two rows, while Ptychopteris is applied to decorticated stems. These terms are used for stems belonging to one generic type and possessing the structure of Psaronius stems. The researches of Grand'Eury^ led to the discovery that certain Psaronius stems bore fronds of the Pecopteris type some of which bore sori of the Asterotheca or Scolecopteris type. The same
. Fossil plants : for students of botany and geology . Paleobotany. 414 PSARONIEAE [CH, is applied to steins exhibiting spirally disposed leaf-scars like those of recent tree-ferns; in Megaphyton the scars are dis- tichously arranged, in two rows, while Ptychopteris is applied to decorticated stems. These terms are used for stems belonging to one generic type and possessing the structure of Psaronius stems. The researches of Grand'Eury^ led to the discovery that certain Psaronius stems bore fronds of the Pecopteris type some of which bore sori of the Asterotheca or Scolecopteris type. The same author^ has also contributed many interesting facts,. Fig. 295. Psaronius stem with roots. (Much reduced. After Grand'Eury.) obtained by an examination of the relation of Psaronius stems to the sediments of French Coal-fields in which they occur, in regard to habitat and manner of growth. The specimen represented in fig. 295 shows a portion of a Psaronius stem, the upper part of which illustrates the Caulopteris state of preser- vation, while the lower part is covered by a mass of roots. It is probable, as Rudolph^ suggests, that this rich development of roots, which gives to an old Psaronius stem the appearance of an ' Ciraiid'Eury (77) A. ^ Budolph (05). - Grand'Eury (77) A; (90) 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
