94 NOTICES OF BOOKS AND MEMOIRS. 



for the most part carried on in Prof, de Bary's botanical 

 laboratory at Strasburg, and the whole is an excellent piece of 

 work. The morphology of the vegetative organs is treated of in 

 great detail, especially the leaf arrangement, a brief account of 

 which was communicated by Dr. Balfour to this Journal last year 

 (1878, p. 290). The structure of the flowers is fully described for 

 the first time ; they are unisexual, but it is not determined whether 

 monoecious or dioecious. The pollen-cells are united to form chains, 

 but are not so long as in the allied genera Zostera and Cymodocea. 

 The female flower has an inferior ovary with numerous ovules on 

 three parietal placentas ; this is terminated by a slender process 

 (perianth-tube ?), which bears at its apex the three small 

 perianth-segments alternating with the- carpels, and within these 

 three long filiform stigmas. The fruit is a globular capsule ; the 

 seeds exalbuminous ; the large macropodous embryo with a 

 coiled cotyledon at the summit. In his remarks on the systematic 

 position of the genus, the author observes that, though possessmg 

 many of the characteristic marks of the XaiadacecB, where it is 

 usually placed, Halophila b}^ the structure of its ovary and in other 

 points agrees with the HydrocharidecB, and must be regarded " as a 

 form breaking down the artificial distinction separating the two 

 families, unless indeed one places it altogether in the Hydrocharidea;.'' 

 The species examined by the author, H. ovalis and H. stipidacea, 

 were both collected at Eodriguez. Dr. Balfour attaches great 

 importance to the foliage, and in opposition to Ascherson and 

 Bentham would remove both H. spinulosa and H. Beccarii from 

 the genus on account of their very different leaves. H. T. 



The number of special cryptogamic periodicals is on the 

 increase ; besides the old established ' Hedwigia ' and ' Grevillea ' 

 we have the ' Eevue Bryologique ' of M. Husnot and the ' Brebis- 

 sonia ' or ' Eevue d'algologie ' of M. Huberson, and now, with the 

 title of ' Eevue Mycologique,' a new journal, devoted to the study 

 of Fungi, has appeared under the editorship of M. C. Eoumeguere. 

 It is a quarterly, and the first number was issued on January 1st 

 containing forty-four pages and a plate. The subscription is 12 fr. 

 a year. Address, M. C. Eoumeguere, Eue Eiquet 37, Toulouse. 



The collection of plants made by Prejevalsky in his last 

 expedition, together with the rich one of Potanin made on the 

 borders of Mongolia, is being worked out by Maximowicz and 

 Eegel, and the results will be embodied in an illustrated work on 

 the Flora of Mongolia and Kansu, a large number of the plates 

 for which are ready. 



The Eev. W. A. Leighton announces that he has nearly 

 completed the printing of the third edition of his ' Lichen-Flora 

 of Great Britain, Ii-eland, and the Channel Islands,' which 

 it is expected wiU be ready for issue early in March. This new 

 edition is rendered necessary by the numerous discoveries of 

 Mr. Larbalestier in the West of Ireland ; those of Mr. Crombie, 



