456 NOTES AND MEMORANDA. 



of determining the species of Agaricus, the mycelium of which is the 

 canse of the disease. In a note read before the French Academy,* 

 he now identifies it as Agaric7is melleus Vahl, of which he considers 

 A. griseoftiscus DC, and A. Mori Fr., to be mere varieties. The 

 mycelium of this fungus, known to older authors as Bhizomorpha 

 fragilis, attacks the roots of a variety of trees, as the mulberry, chest- 

 nut, horse-chestnut, lilac, apple, and vine. This mycelium occurs in 

 three different forms — (1) filamentous or byssoid, which has been 

 seen to proceed directly from the spore, and which attacks especially 

 the root of the vine ; (2) radiciform or rhizomorphic (Rhizomorpha 

 fragilis suhterranea of authors), smooth and brown, with tufts of red 

 filaments, comparable to the sclerotia of other fungi ; and (3) mem- 

 branaceous or hymenoid (Bhizomorpha fragilis coriicalis), which pene- 

 trates in the form of flat expansions, between the layers of the bark, 

 into the cambium zone, and even into the wood itself. 



Conidia of Fistulina hepatica. — As long ago as 1864, Seynes 

 described certain spore-like bodies which he found on the upper 

 surface of the receptacle of this fungus ; and the observation was con- 

 firmed by Leveille, Thuret, and Bornet. G. Arcangeli has submitted 

 these bodies to a fresh examination,! and confirms in all important 

 points the observations of Seynes. The conidial region of the recep- 

 tacle is easily recognized by its more intensely red colour. The 

 conidia are oval or ellipsoidal, varying in length from 0*006 to 

 0-01 mm., and in breadth from 0-004 to -005 mm.; and they are 

 borne, in larger or smaller numbers, on delicate conidiophores, 

 the whole being of a tawny colour. Arcangeli has no doubt that 

 these conidia belong to the Fistulina itself, and not to another fungus 

 parasitic upon it. He considers that the presence of these organs 

 indicates a transition from the Polyporei to the Gasteromycetes which 

 are furnished with more than one kind of reproductive organs. 



Algae. 



Morphology and Biology of the Phycochromaceae. — Professor 

 Borzi,| of Vallombrosa, has worked out a classification of one of the 

 lowest and least studied groups of chlorophyll-containing Thallo- 

 phytes, the Pbycochromaccfe (known to some writers as Phyco- 

 chromophycefe), called by Cohn Schizophyta, to correspond with the 

 analogous Schizomycetes of the non-chlorophyll-containing Thallo- 

 phytes. This group he classifies as follows : — 



Ord. I. Nematogen^ Eabh. Cells united into linear filaments. 

 Sub-ord. 1. Hormogeneae Thr. (Nostochinece pi. auct.). Multi- 

 plication by means of hormogonia (mobile fragments of 

 filaments). 



Fam. 1. Nostochacece Eabh. Filaments of cells vermi- 

 form, simple, usually interrupted by heterocysts; 

 increase indeterminate ; spores. 



* ' Comptes Rcndiis,' Ixxxviii. (1870) 65. 



t ' Nuov. Giom. Bot. Ital.,' x. (187S) oUl>. J Ibid., 236. 



