ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 385 



nine canal cells. 14. The breaking down of the canal row may begin at 

 any point, is frequently acropetal, but never involves the ventral canal 

 cell. 15. The ventral canal cell is persistent, behaves for a time exactly 

 as does the egg, but normally disintegrates just before the archegonium 

 opens for fertilization. 1(5. Abnormalities, such as double venters, 

 multiple eggs, etc., are of common occurrence. 17. The archegonium 

 of Sphagnum is synthetic, combining certain characters of the Hepatieae 

 with those of the Musci. 



Plagiochasma.* — A. W. Evans gives an account of the thalloid 

 hepatic genus Plagiochasma and of its North American .species, a 

 revision of which was badly needed. In an historical introduction the 

 author tells how the generic name was proposed in 1832, and why he 

 prefers this name to the older Aytonia, Rupinia, etc. He tells also, 

 briefly, when and where the various species have been created, and which 

 species have been shown to be synonyms, the result being that thirty- 

 four species are accepted and four left as doubtful. Passing on to the 

 morphology and anatomical structure of the plant, he describes the 

 thallus, the epidermis and pores, the photosynthetic and-ventral tissues, 

 the rhizoids and ventral scales, the male and female inflorescences and 

 reproductive organs, the sporophyte, spores, and elaters. He discusses 

 also the significance of the carpocephalum, and the views of botanists 

 concerning it. He then describes each of the six North American 

 species, giving figures, synonymy, distribution, and critical notes, and he 

 appends a bibliography. 



Pedicel of Lunularia vulgaris, f — P- Lesage describes some ex- 

 periments made upon the hepatic Lunularia vulgaris. The pedicel of 

 the female capitulum remains abbreviated until the spores are ripe, 

 whereupon a rapid elongation of the pedicel, to about 25 mm., takes 

 place. The author prevented this normal elongation from being com- 

 pletely carried out by covering the plants down. As a result the 

 pedicel remained more or less dwarfed (say 14 mm.), but the normally 

 short stalks (2 • 25 mm.) of the sporangia took up the growth and 

 became abnormally long (3 ' 50-4*0 mm.). This means that the 

 stimulus of growth, which normally works itself out upon a part of the 

 oodhyte, passed on to the sporophyte, and stimulated its tissues to an 

 abnormal growth. The author found that the extra growth of the 

 sporangia! stalks was in part due to the moist atmosphere caused by 

 covering down the plant, but in part only, 



Bryophyta of Denmark. J — C. Jensen publishes the first part of a 

 flora of the Bryophyta of Denmark and the Faroe Islands, in which he 

 describes the Hepaticales, Anthocerotales, and Sphagnales. After treat- 

 ing of the general structure, classification, conservation, etc.. he gives 



* Bull. Torrev Bot. Club, xlii. (1915) pp. 259-308 (figs.). 

 t Comptes Rendus, clx. (1915) pp. 6' 7 9~81 



X Danmarks Mosser. .1. Kobenkavn : Gyldendalske Boghandel (1915) p. 317 

 (figs.). 



