ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 207 



five of these occur in North America. One of the generic characters is 

 the postical origin of the branches ; but some of the American species 

 vary markedly in this respect, and deviate also with regard to the mouth 

 of the perianth and the development of the under-leaves. The author 

 considers that the genus is distinct from both Anomodada and Cepha- 

 lozia, and regards the position of the branches as liable to be influenced 

 by the environment of the plant. The trigones and the thickenings of 

 the cell-walls are characters of generic and specific importance. The 

 under-leaves present peculiarities which have been much overlooked 

 hitherto, especially the slime-secreting papilla? on the margins. Under- 

 leaves occur in all the American species. The apical thickening of the 

 female branch after fertilisation is another character that deserves more 

 attention. The gemmiparous branches are of use in specific discrimi- 

 nation. The author gives the distribution and synonomy of the five 

 North American species, with full descriptions of 0. Macounii, 0. 

 Gibbsice (sp. n.) and 0. prostratum, also of 0. portoricense, an exotic 

 species which resembles Anomodada mucosa. 



Hepaticse of Puerto Rico.* — A. W. Evans also gives a critical ac- 

 count of the four genera Harpahjunea, Cyrtolcjeanea, Eiwsmolejeanea, and 

 Tradiyhjeunea, based upon material gathered by himself and by Heller 

 in Puerto Rico. He restricts HarpaUjeunea to Spruce's well-marked 

 section Cardiostipa, and describes two new species (//". subacute and 

 H. heterodonta). Cyrtolejeunea is a new genus established for the recep- 

 tion of C. holostipa, a species about whose systematic position great 

 diversity of opinion has been expressed hitherto. In all, the paper treats 

 of eight species, with full descriptions and figures, and comparative notes 

 on allied species and genera. 



Pallavicinia Flotowiana.f— F. Cavers gives a detailed morpho- 

 logical description of this plant which grows in Coatham Marshes, Yorks. 

 It belongs to the subgenus Mordcia, and is synonymous with P. hibernka 

 var. Wilsoniana. The most interesting feature in its structure is the 

 presence of two lateral strands of water-conducting tissue ; their func- 

 tion was easily demonstrated in living plants ; but these strands were 

 not differentiated in plants which had been cultivated in moist covered 

 dishes — a modification which the writer has observed in laboratory 

 cultures of other thalloid hepatics. The sexual organs and the de- 

 velopment of the sporogonium are described. 



Fegatella conica.J — F. Cavers also describes in detail the structure 

 and biology of FegaUtta conka under the following headings : Apical 

 growing-point and branching ; Air-chambers ; Ventral tissue ; Ventral 

 scales ; Rhizoids ; Mycorhiza ; Asexual reproduction ; Sexual organs ; 

 Sporogonium ; Germination of the spore. The high degree of differen- 

 tiation attained by the thallus is indicated by the evaporation-tissue in 

 the air-chambers and the mucilage-organs in the mid-rib. The presence 

 of the symbiotic mycorhiza is indispensable for the normal development 



* Bull. Torrey Bot. Club, nx. (1903) pp. 544-G3 (3 pis.). 

 t Naturalist, 1903, pp. 441-4, 451-5 (1 pi. and 5 figs, in text). 

 % Ann. Bot., xviii. (1904) pp. 87-120 (2 pis. and 5 figs, in text). 



