ZOOLOGY AND BOTANY, MI0KO8COPY. ETC. 247 



The filiform bodies found in the tubercles are, according to Praz- 

 mowski, true hyphae-filaments, as Ward has already proved ; * he does 

 not, however, think w^ith Ward that they enter the root only through 

 the root-hairs, but also through the young epiderm. The tubercles he 

 finds invariably to be formed only vphere the fungus-hyphas penetrate 

 the tissue of the root. They branch copiously in the epidermal cells. 

 As soon as the hyphae reach the lower layers of the bark, the trans- 

 ference of formative materials into them commences. The first 

 substance produced in them is starch ; subsequently in the inner part 

 of the tuber is formed the so-called " bacteroid-tissue," in which are 

 found the peculiar bodies regarded by some observers as of the nature 

 of bacteria, or detached portions of the fungus-hyphge, by others as 

 simply unorganized food-materials. The author does not agree altogether 

 with either of these views ; he regards them as internal protoplasmic 

 structures found within the fungus-hyphsB before the development of 

 the " bacteroid-tissue." Their form varies in different species ; in 

 Phaseolus and Liipinus they maintain during their whole existence the 

 form of bacterium-like rods ; in Pisum, Medicago, and Vicia they 

 branch ; in TrifoUum they are usually pear-shaped. 



With regard to the nature of the fungus, the author regards it as 

 belonging properly neither to the Hyphomycetes nor to the Myxomy- 

 cetes, but presenting in some respects the closest analogy to Plasmo- 

 diophora Brassicse, differing from this chiefly in having, in an early 

 stage of its existence, a filiform state, and in the peculiar " bacteroids " 

 contained within its hyphse. It is possible that these, although not 

 true spores, may have a reproductive function, and may possibly, 

 under certain conditions, develope into plasmodes. With respect to 

 the function of these tubercles, the author is disposed on the whole to 

 agree most with Hellriegel's view that the connection between the 

 plant and the fungus is a symbiotic one, and that the fungus enables 

 the host in some way to avail itself, in its nutrition, of the free nitrogen 

 of the atmosphere. 



The observations were made chiefly on the species above-mentioned, 

 but the following agree also in the general facts : — Vicia sativa, 

 V. Faha, Lupinus angustif alius, L. luteus, L. perennis, TrifoUum pratense, 

 T. hybridum, Medicago sativa, and M. lupulina ; the phenomena differing 

 only in unimportant points in the difterent species. 



Tubercles of Leguminosse.f — M. P. Vuillemin describes, in the root- 

 tubers of Medicago disciformis and Galega officinalis, the occurrence of a 

 CladocJiytrium, which produces its sporanges and uniciliated zoospores 

 at the end of the winter when the tubercles are quite mature. The 

 " bacterioids " he regards, with Brunchorst, as simply fragments of the 

 protoplasmic network. The anatomical structure of the tubercles 

 themselves he compares to that of the aggregated buds of Petasites, 

 resulting from the isolation of the fibrovascular bundles. 



Formation of Subterranean Swellings in Eranthis hyenialis.|— 

 M. P. A. Dangeard states that the first subterranean swelling of the 

 winter aconite includes the upper part of the principal root, the hypo- 

 cotyledonary axis, and the region of insertion of the cotyledonary 



* Cf. this Jourual, 1887, p. 788. 



t Ann. Sci. Agron., i. (1888) 96 pp. and 2 pis. See Morot's Journ. de Bot., ii. 

 (1888) Rev. BibL, p. 153. % Bull. Soc. Bot. France, xxxv. (1888) pp. 366-S. 



