. Devonian floras; a study of the origin of Cormophyta. Paleobotany -- Devonian. 64 THE ARCIIAEOPTERIS FLORA [CH. moment it may be retained as a distinct tyj^e in a position close to Sphenopteridium. Sphenopteris, Brongniart, 1822. This well-known but well- nigh indefinable type of compound frond with rounded pinnules, more or less deeply lobed and contracted at the base, appears to be rarer in Devonian rocks than Sphenopteridium. It, however, occurs in England, Ireland, Belgium and several other regions in Upjjer Devonian rocks. Distribidion. From Upper Devonian onwards. Lycopsida. Bnthrodend
. Devonian floras; a study of the origin of Cormophyta. Paleobotany -- Devonian. 64 THE ARCIIAEOPTERIS FLORA [CH. moment it may be retained as a distinct tyj^e in a position close to Sphenopteridium. Sphenopteris, Brongniart, 1822. This well-known but well- nigh indefinable type of compound frond with rounded pinnules, more or less deeply lobed and contracted at the base, appears to be rarer in Devonian rocks than Sphenopteridium. It, however, occurs in England, Ireland, Belgium and several other regions in Upjjer Devonian rocks. Distribidion. From Upper Devonian onwards. Lycopsida. Bnthrodendron, L. et H., 1885 (Fig. 37). This well-known genus is of frequent occurrence in Devonian rocks. There has been some ten- dency to include the Devonian species in a distinct genus Cyclostigma^, as originally suggested by Haughton in 1859. This, however; can now hardly be justified^. There is little doubt that the best known of the Devo- nian species, B. Kiltorkense, occurring in Ireland and Bear Island, is a thoroughly typical representative of the genus, as the recent studies of Nathorst and Johnson clearly show. Practically all the organs of B. Kiltorkense are now known. The lower part of the trunk consists of a Stigmarian rhizophore, the features of which agree closely with the Stigmarias of the Coal Fig. 37. Bothrodendron Kil- torkense, (Haugh.), from the Upper Old Red of South Ire- land. Stem with leaf scars. (Reduced |- nat. size.) Speci- men No. 20 Devonian Plant Coll., Sedgwick Museum, Cambridge. ( photo.) According to Johnson^, " the leaves are cleai-ly arranged in whorls at first, but become distant and quincuncially arranged in older stems, owing to 1 This term is in any case several times preoccupied by recent Angiosperms. 2 Johnson (1913), especially p. 505. " Ibid. (1913), pp. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of
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