554 SCIENCE PROGRESS 



Coniferen," Ark. f. botanik k. svensk. vetenskapsakad. , vol, xvi, 

 no, 6, pp, 1-32, pi. i, 1920), who has added to the now rapidly 

 increasing data derived from careful study of the cuticular 

 preparations. Florin endeavoured to find essential characters 

 in the stomata of several recent genera, and then examined 

 carefully cuticle preparations of the fossils Sequoia Langsdorfti 

 Heer, and Taxodium distichum Rich, fniocenuin Heer, which 

 he illustrated with good photographs. He supported the earlier 

 diagnoses of the fossils as belonging to the genera to which they 

 were allotted by older workers. 



Earlier Gymnosperms are represented by the detailed 

 anatomical work of Scott on the fertile shoot of Mesoxylon 

 {Ann. Bot., vol. xxxiii, pp, 1-21, pis, i-iii, 1919) and on 

 Ginkgo by Nathorst {Geol. Foren. fork., vol, xli, pp, 234-48, 

 text figs., 1 919). The fertile shoots of Mesoxylon multirame 

 were found to be identical with the previously known axillary 

 shoots ; and that they were what would be described as 

 Cordaianthus from impression-material was also evident. The 

 shoot was bi-laterally symmetrical, and the vascular strands 

 were individually mesarch. The place of Mesoxylon within the 

 family of Cordaiteae is thus finally and completely established. 

 Nathorst 's contribution dealt with the unique genus Ginkgo, as 

 represented by Tertiary forms in Spitzbergen, in particular by 

 the very widely distributed G. adiantoides. 



The Cycadophyta were considered in general by Wieland 

 (" Classification of the Cycadophyta," Amer. Jour. Sci., vol. xlvii, 

 1919, pp. 391-406), who re-discussed a number of early theories, 

 and who gave a tabulated list of all the genera of this great 

 group arranged according to his current views. Florin {Arkiv. 

 f. botanik, K. svensk. vetensk., vol. xvi, 1920, pp, i-io, pi. i) 

 described of the leaf oi Nilssonia polymorpha (the genus Wieland 

 placed in his Holophytse) the cuticle with stomates. He then 

 entered into a consideration of the classification and systematic 

 position of the genus Nilssonia ; the omission of all reference 

 to the only member of the genus of which the internal anatomy 

 is known (A'', orientalis, see Stopes, Ann. Bot., vol. xxiv, 

 pp. 389-93, pi. i, 1 910) renders this consideration incomplete. 

 The first " baby " of the group to be described from Europe 

 was named by Stopes Bennettites Scottii {Jour. Linn. Soc. Bot., 

 vol. xliv, pp. 483-96, pis. xix, XX, text figs,, 1920), The 

 stem (of exceedingly small size) and its still enfolded young 

 leaves, were well preserved anatomically, and described in full 

 from a series of sections. This specimen elucidated a point 

 long rather obscure in the mature American forms, and showed 

 that there was a thick weft of hairs on the under surface of 

 the leaves, 



A great gap, both in phylogenetic and geological sequence. 



