572 SCIENCE PROGRESS 



the leaves and young shoots of Elm, Lime, Hornbeam, Willow, 

 and Poplar are not to be despised. Useful data are furnished 

 as to the quantities in which these various fodders can be 

 supplied, together with analyses showing the proportion of 

 nitrogenous material, fatty material, and hydrocarbons which 

 they contain. 



Morphology. — Prof. Marloth, dealing with the occurrence of 

 bulbils in South African plants (S. A. Jour. Set., April 191 7), 

 calls attention to the fact that of the twelve examples cited, 

 nine either do not fruit or fail to produce seed. The question 

 arises, Is the barrenness a result of bulbil formation or is the 

 latter an outcome of the former ? The production of bulbils by 

 a sterile hybrid Micranthus and by Gladiolus cuspidatus when 

 the latter is attacked by Uromyces gladioli leads the author to 

 support the second alternative. 



Two important papers dealing with the gametophytes of 

 Psilotum and Tmesipteris appear in the Transactions of the 

 Royal Society of Edinburgh (vol. lii. pt. 1, Nos. 3 and 4). In the 

 first of these Mr. Darnell-Smith describes in particular the spore 

 and germination of Psilotum, and in the second Prof. Lawson 

 describes in detail the structure of the prothallus of Psilotum 

 and of Tmesipteris. In both genera the gametophytes are 

 remarkably alike. The main body is branched, cylindrical 

 in form, and of a light brown colour. Associated with the 

 absence of green pigment and the subterranean habit, the 

 nutrition is saprophytic and entirely dependent upon an 

 endophytic and non-septate mycorrhizal fungus. This latter 

 is not, as in the gametophytes of Lycopodium, confined to a 

 definite zone, but distributed throughout the adult pro- 

 thallial tissue. 



Numerous rhizoids are developed from the surface and 

 growth takes place by means of apical meristems terminating 

 each branch of the gametophyte. Both antheridia and arche- 

 gonia occur on the same prothallus. The former are developed 

 from superficial cells, and at maturity are spherical structures 

 with a single layered wall containing numerous coiled multi- 

 ciliate gametes. The most striking feature, which distin- 

 guishes these antheridia from those of either Equisetacece or 

 Lycopodiacece, is that they project from the surface in place 

 of being embedded in the prothallial tissue. 



The archegonia like the antheridia arise from any part of 



