312 SUMMARY OF CURRENT RESEARCHES RELATING TO 



upper octant the first divisions of the sub-epidermal cell closely resemble 

 those observed in Myosurus minimus ; the subsequent fate of the result- 

 ing cells is uncertain, but they appear to represent part of two tetrads 

 of initial-cells of the cortex and tissue between the latter and the 

 dermatogen ; it is from this region that the two cotyledons take their 

 origin. 



A comparison of the embryology of the Ranunculacea? and the 

 Cruciferse shows that the former is the more primitive, being characterized 

 by extreme simplicity and regularity of division, while the latter shows 

 more tendency to adaptation and to processes tending to acceleration of 

 the various phenomena of development. 



CRYPTOGAMS. 



Pteridophyta. 

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



Sorus and Prothallus of Peranema.* — R. C. Davie describes the 

 development of the sorus and sporangium and the prothallus of 

 Peranema cyatheoides D. Don. 1. The sorus arises superficially on the 

 under side of the leaf ; it has a basal indusium of cup-type, with one 

 portion of the cup suppressed in development, and the other over-arching 

 the receptacle and becoming contracted at its rim ; the receptacle is of 

 the Gradate type ; the central part of the stalk of the sorus is 

 continuous with the receptacle, and tlie peripheral part is continuous 

 with the indusium. 2. The early sporangia arise in basipetal sequence ; 

 the mature sorus is a mixed one. 3. The sporangium in its early 

 segmentation sometimes follows the Cyatheaceous type, sometimes the 

 type of the Polypodiaceae. 4. The prothallus bears glandular hairs, 

 sometimes slightly raised above the level of the surface upon unicellular 

 bases ; the antheridium has been found in every case but one to have 

 an undivided lid-cell. 5. On a general comparison of the features of 

 Peranema and the closely related genera in the Woodsieaj-Woodsiina; 

 group of Polypodiaceae, the following grouping is suggested : — Woodsia 

 — Diacalpe — Peranema. Woodsia comes nearest to the Cyatheaceoe, 

 Peranema to the Polypodiacea;. 6. The mature sorus of Peranema is 

 held to be related to that of Nephrodiiim, and a phyletic line is traced 

 from the Cyatheaceje to the Aspidieas group of Polypodiacese. 



Wound Reactions in Petioles of Pteris aquilina.f— H. S. Holden 

 pubhshes some observations on the wound reactions of the petioles of 

 Pteris aquilina. 1. Petioles of wild Pteris aquilina often show wound- 

 scars. The majority of the wounds are very superficial, not penetrating 

 the sub-epidermal sclerenchyma ; others are deeper seated. 2. The 

 wound reactions are somewhat variable, but are characterized by (i) a 

 compensatory local thickening, and partial or complete lignification of 



* Ann. Bot., xxx. (1916) pp. 101-10 (1 pi. and 3 figs.), 

 t Ann. Bot., xxx. (1916) pp. 127-34 (4 figs.). 



