534 SUMMARY OF CURKENT RESEARCHES RELATING TO 



1 • 2 and 1 ' 55, and for the willow between 1 • 85 and 2 • 1. Another dis- 

 tinguishing feature is that the pits on the radial walls are found in the 

 second or thii'd row of cells of the stem and the fourth row in the root 

 of the poplar, while in the willow thej are found from the second to the 

 tenth, but usually from the fourth to the sixth row of both root and stem. 



CRYPTOQAMS. 



Pteridophyta. 



(By A. Gepp, M.A., F.L.S.) 



Anatomy of Palaeozoic Ferns.* — P. Bertrand writes at some length 

 upon the anatomical study of the palfeozoic ferns and the problems 

 which they raise. His object is to show that the internal structure 

 affords d(;finite characters which permit a determination and strict 

 classification of the fossil specimens. All sucli anatomical research 

 comprises three essential operations : — (1) Study of the ramification ; 

 (2) study of che ligneous differentiation ; (3) comparison, as far as 

 possible, with types of the same epoch. The pala30zoic ferns, whose 

 structure remains preserved and has been described, fall into three large 

 groups :— Osmundacese, luversicatenales or Botryopteridese, Paaronieas. 

 The steps of the work are as follows : — (1) The recent Osmundaces ; 

 (2) the Permian Osmundacea? ; (3) the luversicatenales : — (a) the 

 frond ; (b) the stipes ; (c) " I'etoile libero-ligneuse fihcineenne " ; (d) 

 general phylogenic problems raised by the anatomy of the Inversicaten- 

 ales ; (4) problems relating to the Psarouiese ; (5) general conclusions. 



Zygopteris G-rayi.f — D. H. Scott gives an illustrated account of 

 the structure of the palaeozoic fern, Zygopferis Grayi of Williamson, 

 after studying sections of a new specimen. Having peripheral loops on 

 the leaf-trace, the species must be classed in the genus A^ikyropferis, as 

 had been indicated by P. Bertrand. The stele in transverse section is 

 a five-rayed star. The vascialar system of AnJcyropteris may be regarded 

 as a highly elaborated protostele rather than as a condensation of a 

 polystelic structure. Aphlel)iffi occur abundantly on the stem and the 

 leaf-base ; they are modified basal piumv of the leaf, as shown by the 

 structure and mode of origin of their vascular strand. Anhyropteris is 

 closely akin to Aster ochlaena. 



Roots of Psaronius.J — H. Graf zu Solms-Laubach gives an account 

 of the root-system and root-structure in Fsaronius. a paleozoic Marattia- 

 ceous fern. In modern Marattiaceae the roots bore their way out through 

 the stem-cortex to the surface. In Fsaronius the roots form a wide 

 zone in a cortex which contains no leaf-traces, no leaf-scars. Solms- 

 Laubach finds that Psaronius had a thin cortex beneath the massive 

 hypodermal sclerenchyma ; and outside the stem there subsequently was 



* Progressus Rei Botanicas, iv. (1912) pp. 182-302 (59 figs.). 

 + Ann. of Bot., xxvi. (1912) pp. 39-69 (5 pis. and fig.). 



% Zeitschr. Bot., iii. (1911) pp. 721-57 (figs.) See also Bot. Gaz., liv. (1912) 

 pp. 81-2. 



