ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 163 



Bryophyta. 



Morphological Study of Pallavicinia Lyellii. — Aethur W. Haupt 

 {Bot. Gaz., 1918, 66, 524-32, 5 pis.). This species belongs to the 

 sub-genus Eupallavicinia, its vegetative body consisting of a single pro- 

 strate portion. The apical cell is of the dolabrate type. Branching is 

 both apical and adventitious. The species is dioecious, as usual in the 

 genus. The antheridia are situated in two parallel rows on each side of 

 the midrib, and are protected from behind by an involucral upgrowth. 

 Their development, with minor variations, follows the type for the 

 anacrogynous Jungermanniales. The archegonia are in dorsal groups, 

 and are surrounded by an involucre and a perianth, the latter remaining 

 inconspicuous until after fertilization. The young archegonial stalk 

 consists of two cells. The egg is small, and the neck long and twisted. 

 The lower half of the fertilized Q^g becomes a haustorial organ and con- 

 tributes nothing to the development of the foot, seta, or capsule. The 

 calyptra is four or five cells in thickness, in this respect differing from 

 that of SympMjogyna. The differentiation of the spores and elaters 

 occurs relatively late in the development of the sporophyte, and follows 

 the method of Symphyogyna. A sterile cap is present at the apex of the 

 capsule, and remains intact in dehiscence, which is accomplished by 

 means of four longitudinal slits. A. G-. 



Taxonomic Study of Dumortiera. — Alexander "W. Evans {Bull. 

 Torrey Bot. Club, 1919, 46, 167-82). A history of the genus Dumor- 

 tiera, a critical study of the species that have at various times been 

 referred to it, and a detailed discussion of the characters adopted by 

 different authors for discriminating the species. Evans shows that the 

 characters drawn from the size and ramification of the thallus are especi- 

 ally untrustworthy, and that those based on the female receptacle and 

 the spores are scarcely more satisfactory. On the other hand, he finds 

 that the structural features of the vegetative thallus afford charac- 

 ters which clearly distinguish the only two species that deserve to be 

 maintained — viz. D. hirsuta, with a smooth upper thalline surface ; and 

 D. nepalensis, with crowded papilliform cells on the upper thalline 

 surface, and always showing vestigial air-chambers. D. hirsuta has a 

 very wide geographical distribution, mostly tropical. D. nepalensis is 

 absent from Europe and Africa, but otherwise has a similar range, but 

 is more abundant in South-east Asia. A. Gr. 



American Species of Marchantia. — Alexander W. Evans {Trans. 

 Connecticut Acad. Arts and Sciences, 1917, 21, 201-313, figs.). A 

 revised monograph of the species of Marchantia recorded from North and 

 South America. Gottsche, Lindenberg and Ness, in their Synopsis 

 Hepaticarum (1847), recognized sixteen such species, and Stephani in his 

 Species Hepaticarum (1899) gave a total of eighteen. The present 

 careful revision reduces them to nine, grouped in two sections : — (1) 

 Astromarchantia, including if. polymorpha, M. plicata, M. Berteroana ; 

 (2) Chlamidium, including M. paleacea, M. hreviloba (a new species 

 from Jamaica), IT. domingensis, 31. papillata, M. Bescherellei, 31. cheno- 

 poda. Each species is described, figured and discussed, and a chapter is 



