II 



I^H 



XLII] PSYGMOPHYLLUM $1 



assigned by some authors to Ginkgophyllum there are no marginal 

 veins like those in the lamina of a Ginkgo leaf. This objection, 

 though not in itself fundamental, is based on a sound principle, 

 namely an objection to the assumption of affinity to Ginkgo implied 

 by Ginkgophyllum, an assumption that rests on a superficial 

 resemblance unsupported by any evidence of real value. 



The name Psygmophyllum is adopted both for entire and deeply 

 divided leaves of larger dimensions than the similar leaflets of 

 fronds included in such genera as Palaeopteris and Adiantites. 

 Specimens usually occur as detached leaves, but when the leaves 

 are attached to an axis the lamina is usually contracted into a 

 fairly long, decurrent, basal portion ; there is no true petiole. 



The veins spread from the base of the lamina and are repeatedly 

 forked ; they may be very numerous and in some forms occasion- 

 ally anastomose, as in P. flabellatum, or much farther apart, as in 

 P. majus Arb. and P. Brownii (Daws.). The genus is at best a 

 purely artificial one; we know nothing as to the reproductive 

 organs or the anatomical structure, nor is it possible to determine 

 in many instances whether the specimens are portions of compound 

 fronds or shoots bearing simple leaves. 



Psygmophyllum ranges from Devonian to Permian strata, and 

 the Rhaetic leaves named Psygmophyllum ? crenatum (Nath.) are 

 accepted as evidence, the vertical distribution must be extended. 

 The genus occurs in England, Ireland, the continent of Europe, 

 Spitzbergen, and North America ; it is also a member of the 

 Permo-Carboniferous floras of South Africa and India. 



Psygmophyllum flabellatum (Lindley and Hut ton). 



The name Noeggerathia was given by Lindley and Hutton 1 to 

 some specimens from the Newcastle Coal Measures; of the two 

 examples figured one consists of a slender supporting axis bearing 

 several torn cuneate leaves, which they speak of as part of a com- 

 pound frond, and the other is a single leaf or leaflet. It is stated 

 by Prof. Lebour and Dr Arber 2 that the original specimens cannot 

 be found in the Hutton collection in the Newcastle Museum. In 

 Mr Howse's Catalogue 3 a specimen is described as possibly the 

 original of the larger example, and some years ago I examined a 







1 Lindley and Hutton (32) A. Pis. xxvin., xxix. 



2 Arber (12) p. 394. 3 Howse (88) A. p. 109. 

 S. IV 



