56 SUMMARY OF CURRENT RESEARCHES RELATING TO 



margin or the surface of the frond. In DavalUa and Nephrotepis the 

 aorus, marginal in origin, is carried by subsequent growth on to 'the 

 lower surface. The position of the nascent sorus is, like the character 

 of the sporangium, of prime importance, and takes precedence ol the 

 anatomical characters of the axis. 



Bryophy ta. 



(By A. Gepp.) 



Riccia Frostii.* — C. A. Black gives a morphological account of 

 Ricria Frostii — structure of thallus, reproductive organs, sporophyte, 

 s] Hire-formation, etc. The air-chambers originate between adjacent 

 up-growing filaments, and when mature are of various sizes and are 

 separated by unilamellate plates of green tissue. The plants are dioicous ; 

 and the reproductive organs are not definitely grouped. The spore- 

 mother-cell nucleus diminishes gradually in size during the successive 

 mitoses ; no centrosomes or centrospheres were observed. The spore 

 contains a very small nucleus surrounded by food material, principally 

 oil. It has two protective coats ; and later the endospore is formed. 

 The exospore is marked with irregular ridges. In the spermogenous 

 tissue the final division is diagonally placed : no cell-wall was found 

 between the resulting triangular cells. The blepharoplast, originating 

 in an angle of the cell, elongates and becomes applied to the transformed 

 nucleus and terminates in a thickened end bearing two cilia. The 

 number of chromosomes is eight for the gametophyte, and sixteen for 

 the sporophyte. 



Tetraphidopsis.f — H. N. Dixon describes the male inflorescence of 

 the rare New Zealand moss, Tetraphidopsis novae-seel andise, and shows 

 that the plant is identical with the older species Meteorium pustltum 

 Hook. f. & Wils. He also shows that Limpricht was in error in re- 

 ducing Weisia WelwitscMi Schinrp. as a synonym of Campylostelium 

 strictum Solms, the two species being distinct in habitat and in the 

 structure of their leaves, capsule, and peristome. 



Ditrichum and Thuidium.J — H. N. Dixon discusses the history of 

 Ditricli urn jlexifol ium (Hook.) Hampe, a South African moss, and finds 

 that it is identical in structure with some eight other species, which he 

 now reduces to synonymy. The distribution of the plant thus extends 

 from South Africa to Asia, Australia, and South America. He also pub- 

 lishes critical notes on some species of Thuidium from Australasia and 

 Oceania, adding a description of T. orientate Mitt., a new species from 

 Penang. 



Dicranoloma.§ — H. N. Dixon begins a series of studies in the 

 bryology of Xew Zealand by publishing a monograph of the sixteen 

 species of Dicranoloma found in New Zealand. He figures the structure 



* Ann. of Bot., xxvii. (1913) pp. 511-32 (2 pis.). 



t Journ. Bot., li. (1913) pp. 244-7. 



X Journ. Bot., li. (1913) pp. 324-30. 



§ New Zealand Institute, Bui'. No. 3 (Wellington, 1913)29 pp. (4 pis.). 



