Dictydium. 67 



angles in the network. Stem from 2 — 3 times as long as 

 sporangium. 



Dictydium, Sclnad. 



Wall of sporangium single ; permanent rib-like thickened 

 portions radiating from base to apex and joined by numerous 

 thinner transverse bands ; thinner portions of wall situated 

 between the ribs disappearing at maturity, or persistent at the 

 base and forming an imperforate calyculus ; columella and 

 capillitium absent. 



Dictydium, Schrad., Nov. Gen. PI., p. 11 ; Rost., Mon., 

 p. 229 ; Cooke, Myx. Brit., p. 57 ; Sacc, Syll., p. 410 ; Zopf, 

 p. 140. 



The primary, vein-Hke, permanent portions of the sporangium 

 radiate from the base and converge at the apex without 

 becoming much broken up or distorted, although there is 

 usually an indication of a reticulate arrangement near the apex ; 

 these primary ribs are united laterally by straight, thinner 

 portions, hence the arrangement of the skeleton is into more 

 or less regular rectangular meshes. 



Distrih. Europe; N.America; S.America; Ceylon; Australia : 

 species 2. 



Dictydium cernuum, Nees. (f. 183). 



Sporangium globose, cernuous, more or less umbilicate at 

 the apex, reddish brown ; stem elongated, slightly thinner 

 upwards, with a sharp curve near the apex, above which the 

 stem is hyaline and shrivelled at maturity ; below the curve 

 dark brown, opaque, smooth, passing into a small hypothallus ; 

 calyculus small ; mass of spores purple brown ; spores globose, 

 smooth, 5 — 7 fj. diameter. 



'Dictydium cernutcvi, Nees., Syst., f. 117; Rost., Mon., p. 229, 

 figs. 17, 19, 22; Cooke. Myx. Brit., p. 57, figs. 17, 19, 22; 

 Sacc, Syll., no. 1401; Schroeter, p. 106; Raunk., p. 51, Tab. 

 ii. fig. 4. 



Dictydium cernuum, var. laxum, B. and C, Grev. 1873, p. 07. 



J^'xsicc. — Fuckel, Fung. Rhen., 1445 and 2099 ; Syd., Myc. 



