. Devonian floras; a study of the origin of Cormophyta. Paleobotany -- Devonian. 62 THE ARCHAEOPTERIS FLORA [cir. linear or filiform forked lobes as in the type species S. rigidum, Lndw. (Fig. 34). Distribution. Middle Devo- nian to Upper Carboniferous. Cephalopteris, Nathorst^, 1910 (Fig. 36). Axes branched, branches opposite in distichous pairs, each pair connate on one side of the axis and decurrent. Lower portions of branches fertile. Sporangia in dense spherical heads arising from the decurrent base of each lateral branch. Sporangia long, ])ointed, dehiscing ? longi- tudinally. Sterile fo
. Devonian floras; a study of the origin of Cormophyta. Paleobotany -- Devonian. 62 THE ARCHAEOPTERIS FLORA [cir. linear or filiform forked lobes as in the type species S. rigidum, Lndw. (Fig. 34). Distribution. Middle Devo- nian to Upper Carboniferous. Cephalopteris, Nathorst^, 1910 (Fig. 36). Axes branched, branches opposite in distichous pairs, each pair connate on one side of the axis and decurrent. Lower portions of branches fertile. Sporangia in dense spherical heads arising from the decurrent base of each lateral branch. Sporangia long, ])ointed, dehiscing ? longi- tudinally. Sterile foliage of the ? Sphenopteridium type, upper portions of branches bearing small dichotomised leafy segments. Distribution. Upper Devo- nian, Bear Island. If Nathorst is correct in correlating certain sterile leaf segments (Fig. 36 (5)) with the fertile main axes—a point on which he expresses no doubt, though to us there seems to be no proof beyond mere associa- tion—then this type is simply a fertile Siihenopteridium, \ni- less in its fructification it is distinct from other members of that genus, the fructifica- tions of which are at present quite unknown. For the. Fig. 35. Spheuopteridium KeiUiaui, Nath., from tlie Upper Devonian of Bear Island. (Nat. size.) After Na- thorst (1902). 1 Nathorst (1902), first described under the name Cephalotbeca in tliat 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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