. Devonian floras; a study of the origin of Cormophyta. Paleobotany -- Devonian. 28 THE PSILOPHYTON FLORA [ Fig. 10. Thursophyton Milleri, (Salt.) from the Middle Devonian of Western Norway. Sterile axes with scale-like emergences. After Nathorst (1915). 1 Kidston (1893), p. 108. thick, short (rudimentary or broken) distant ; The leaves here are pyramidal and thorn-like. \^'ith regard to the mor- phology of these spine-like processes, Kidston^ has con- cluded that these are not" the bases of leaves, as has been suggested, but are the leaves themselves, though developed in
. Devonian floras; a study of the origin of Cormophyta. Paleobotany -- Devonian. 28 THE PSILOPHYTON FLORA [ Fig. 10. Thursophyton Milleri, (Salt.) from the Middle Devonian of Western Norway. Sterile axes with scale-like emergences. After Nathorst (1915). 1 Kidston (1893), p. 108. thick, short (rudimentary or broken) distant ; The leaves here are pyramidal and thorn-like. \^'ith regard to the mor- phology of these spine-like processes, Kidston^ has con- cluded that these are not" the bases of leaves, as has been suggested, but are the leaves themselves, though developed in a very rudimentary form, as in ; Halle2 says "the append- ages of these stems can hardly be anything but ; To this we may reply that, on the present evidence, they are quite as likely to be emer- gences, especially in view of the similar structures occur- ring in certain species of Psilophyton, to which we ha^•e just drawn attention. On our view the emergences of Ar- throstigma and Psilophyton differ chiefly in size and the variation in this respect in the former genus (which Halle has pointed out), as we have just said, is exactly what we should exjject to find in view of the corresponding varia- tion met with in Psilophyton (see pp. 21 and 22). Halle also confirms Daw- son's conclusion that the stem was vascular, the vas- 2 Halle (1916), p. 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 Arber, E. A. Newell (Edward Alexander Newell), 1870-1918; Arber, Agnes Robertson, 1879-1960. Cambridge, The University Press
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