NOTES ON RECENT RESEARCH. 



1113 



ring of brown matter mentioned above. It would thus appear as though 

 there were some connection between the presence of the air-bubble and 

 this brown matter, for the two nearly always occurred side by side. The 

 curious shape of the bubble suggests its having been formed on the plant 

 itself, which was by this agency enabled to float on the surface of the 

 water. All my attempts to elucidate this point have as yet proved un- 

 successful, as the bubbles break up soon after the plant is removed from 

 its floating position. The substance forming the brown ring is undoubt- 

 edly ferric oxide, or some ferric salt. The same is very commonly found, 

 forming a coating on the basal disc of this and other species of (Edogo- 

 nium. It is often present in considerable quantity in places where young 

 plants of this genus are attached to other filamentous Algre. If treated 

 with a solution of potassium f errocyanide, to which a trace of hydrochloric 

 acid has been added, this brown substance is dissolved, and in its place a 

 precipitate of Prussian blue is formed." In his summary, the author 

 remarks that " certain types of root-ends are characteristic for certain 

 species of CEdogonium ; thus the attaching-disc and rhizoid for (Ed. 

 calcareum, capillare, and stagnate, the rhizoid alone for the species from 

 the river Severn, and the attaching-disc and sack-shaped basal end for 

 (Ed. cardiacum.^ This paper is of much interest in connection with the 

 entertaining study of Fresh-water Alga?. — B. I. L. 



Anthracnosb in Okchids. 



Orchid Anthracnose. By M. C. Cooke (Trans. Br. Myc. Soc. 1902). 

 Under this name is described an Orchid disease which appeared before 

 the Scientific Committee (see Journ. xxvi. pp. cxxxix and cxli). The 

 species has been called Glceosporium Bidgoodi, with the following 

 description : — 



Pustules rather large, covered by the blackened cuticle, at length 

 ruptured for the escape of the conidia. The stroma upon which the 

 conidia are produced is also blackened, but the conidiophores become 

 hyaline above, bearing the narrowly elliptic conidia (18-20 x 4 /a) which 

 have two nuclei. No direct evidence that eventually they become uni- 

 septate. On leaves of 0 d onto glos sum. It has been known for six or 

 seven years, but not described. Leaves were submitted to Mr. Bidgood 

 in 1901, who declared it to be a species of Glozospormm but not described, 

 and now it is associated with his name. The conidia of Glceosporium 

 Vanilla are 14-16 x 6-7 v. Those of G. cinctum are 10-15 x 2^-3 fj. 

 Those of G. Oncidii are 14-17 x 4^-6 /u. Those of G. Orchidearum are 

 20-25 x 5-7 p. ; and those of G. affine are 14-20 x 4-6 fj : but other 

 features have to be taken into account as well as the dimensions of the 

 conidia. — M. C. C. 



Growth of Ovules in the Kosace^e. 



Ovule and Seed, Development of, in Rosaeeae. By F. Pechoutre 

 (Ann. Sc. Nat. (BoU) xvi. pp. 1-158, 166 figs. ; 1902.)— The ovules of 

 about thirty species of Bosacece, representing important genera, are de- 

 scribed from the first appearance of the ovule onwards to the mature seed. 

 After an introduction explaining the problems involved, and an historical 



