RECENT ADVANCES IN SCIENCE 305 



their share in the young but progressive science of plant ecology 

 is evidenced by the publication in the same journal (June 

 191 5), of one of the best papers we have yet seen dealing with 

 the ecology of a single plant species — that by Jefferies on the 

 purple heath-grass (Molinia ccerulea), which goes far to solve, 

 as the result of patient field and laboratory work, the puzzling 

 problem presented by the distribution of this plant ; while 

 Marsh contributes an elaborate account of the successions of 

 maritime plant communities as developed at Holme (Norfolk) 

 and worked out by members of the Cambridge Botany School. 

 Fritsch and Salisbury (New Phytol. 14) give a further account 

 of the vegetation of Hindhead Common, resulting from similar 

 co-operative work by members of the Botanical Department 

 of East London College, and dealing mainly with the interesting 

 succession phases observed in the regeneration of heath areas 

 after fires have more or less completely destroyed the previ- 

 ously existing vegetation. 



Flowerless Plants. — Lady Browne (Ann. Bot. 29) has con- 

 tributed a second paper on the anatomy of the cone and fertile 

 stem of Equisetum ; one of the plates accompanying this 

 elaborate memoir must surely be the largest line-block ever 

 published in a botanical paper, having been prepared from a 

 drawing of a model, standing about six feet high, constructed 

 from extensive series of sections, and showing the vascular 

 system of the horsetail cone with remarkable clearness. The 

 fossil genus Bothrodendron is dealt with in the same journal by 

 Miss Lindsey, who brings forward further evidence in favour 

 of the view that the peculiar stem-markings found here and 

 in the allied Lepidodendron are the scars of fallen branches 

 which were cut off by an absciss-layer like that formed at the 

 bases of leaves which drop in autumn. The primitive fern 

 family Ophioglossacese is by way of becoming one of the most 

 exhaustively known plant groups, for on the heels of Lang's 

 elaborate account of the anatomy of all three genera (referred 

 to in Science Progress, 10, p. 135), we have a paper by Petry 

 (Bot. Gaz. 59), on branching of the rhizome in Ophioglossum 

 and Botrychium ; the fact that in the former genus branching is 

 by forking, while in the latter (as also in the third genus, 

 Helminthostachys) axillary buds are regularly present, is taken 

 as emphasising the close relationship of the two latter genera, 

 and the differences between them on one hand and Ophioglossum 



