924 SUMMAKY OF CURRENT RESEARCHES RELATING TO 



succession. This cell is so placed that one side faces the ventral 

 side of the leaf, while the remaining two sides are obliquely disposed 

 with regard to the dorsal side of the leaf. No clearly marked marginal 

 series of persistently active cells has been found giving rise to the 

 pinnse, as has been stated to be the case in typical ferns, and there 

 appears to be no strict relation between the points of origin of the 

 pinnae and the segments cut off from the apical cell. The pinnae 

 arise in acropetal order. The presence of a three-sided apical cell in 

 the leaf of a fern appears to supply an intermediate step towards the 

 more complex leaf of the Marantacece and Gycaclece, and it is believed 

 that this is the first described case of a clearly marked three-sided 

 apical cell occurring in the leaf of any plant. 



Rabenhorst's Cryptogamic Flora of Germany (Vascular Crypto- 

 gams). — This division of the new edition of Eabenhorst's great work 

 has been undertaken by C. Luerssen ; and three parts of this most 

 important contribution to cryptogamic literature are now issued. 

 Luerssen classifies the Pteridophyta or Vascular Cryptogams under 

 three classes, the rilicinse, Equisetinse, and Lycopodinse. The 

 Filicin^ are again divided into Isosporese and Heterosporeee, and the 

 Isosporese into Leptosporangiatee (true ferns) and Eusporangiataa 

 (Ophioglossacese). In the parts now published the sub-order 

 Hymenophyllaceae is treated (one sp. only, Hymenophyllum tunhridg- 

 ense), and of the sub-order Polypodiacese the genera Polypodium, 

 Gymnogramme, Notholcena, Cryptogramme, Adiantum, Cheilanihes, 

 Pteris, Pteridium {Pteris aquilina), Blechnum, Scolopendrium, Aihyrium, 

 and a part of Asplenium. 



Muscineae. 



Braithwaite's British Moss Flora. — Since we last noticed this 

 work,* Parts III.— VIII. have been published, including the Poly- 

 trichaceee (5 pis.) ; Fissidentaceae (3 pis.) ; Leucobryacese (1 pi.) ; 

 Dicranacese (13 pis.) ; and Tortulaceae, Part 1 (6 pis.). 



It is hardly necessary to say that there is no falling off in the text 

 or plates as the work progresses. It is fully up to the expectations 

 formed concerning it before publication, and the text is in every 

 respect worthy of the reputation of the author. He and the draughts- 

 man divide between them the honour of the plates, which are perfect 

 both in drawing and execution. 



Hobkirk's British Mosses.f — This is a new edition of a now well- 

 known handbook, which indeed is the only modern complete guide to 

 the British Mosses. Of these 129 genera and 576 species are de- 

 scribed, with full diagnostic characters and notes of locality. An 

 alteration has been made in regard to classification, as the author 

 no longer follows Bruch and Schimper (through Wilson), but adopts 

 that of Jager's ' Adumbratio Muscorum,' which, however, makes the 

 preliminary synopsis by no means so simple. For collectors of 

 British mosses the book is indispensable. 



* See this Journal, iii. (1880) p. 670. 



t Hobkirk, C. P., ' A Synopsis of the British Mosses,' 2nd ed., 8vo, London, 

 1884,240 pp. 



