dianema] margaritaceae 259 



Spores in mass lilac-grey or drab, when magnified pale yellowish- 

 grey, closely reticulated over the greater part of the surface 

 with raised bands, forming a border 0-5 to 1 //, broad, the re- 

 maining part marked with broken or very loose reticulation, 

 6 to 9 p diam. — Cornuvia depressa Lister in Journ. Bot., xxix. 

 264, t. 311, fig. 2 (1891). 



PI. 190. — a. sporangium ; 6. spores and capillitium showing attachment of the 

 threads to the base and upper wall of the sporangium c. capillitium and spores ; 

 (England). 



This species was first described under the name of Cornuvia depressa, 

 on account of its affinity with Margarita metallica, which was formerly 

 included in the genus Cornuvia. Dr. Rex having since established the 

 genus Dianema for the closely allied American species, it is here 

 adopted as in every way the more appropriate position for this species. 

 The sporangium-wall is usually single, but sometimes has an outer 

 purplish granular layer clothing the membranous layer. 



Hab. On dead wood and sticks. — Batheaston, Somerset (B.M. 2 to 5) ; 

 Rudloe, Wilts (B.M. 19) ; Lyme Regis, Dorset (B.M. 1536) ; Alresford, 

 Hants (B.M. 3163) ; Sutton Coldfield, Warwick (B.M. 3164) ; Bungay, 

 Norfolk (B.M. 3165) ; Tansterne.Yorks (B.M. 3166) ; Sweden (B.M. 3167); 

 Portugal (B.M. 3168). 



3. D. corticatum Lister Mycetozoa, 205 (1894). Plas- 

 modium pink. Sporangia either hemispherical, 1 mm. diam., or 

 more often forming elongated, ring-shaped or net-like plas- 

 modiocarps 3 to 30 mm. long, shining or opaque, chestnut- 

 or purple-brown ; sporangium-wall ochraceous-olive, com- 

 posed of two layers, the outer cartilaginous, densely granular, 

 the inner membranous. Capillitium somewhat sparse, con- 

 sisting of simple or acutely branching slender pale brown 

 threads, 0-5 to 1-5 //.. diam., often showing distant bead-like 

 thickenings, elsewhere either nearly smooth or marked with 

 a single prominent spiral band or for a short distance with three 

 spiral bands ; the threads are attached above and below 

 by very slender extremities to the sporangium-wall. Spores 

 brownish-pink in mass, nearly colourless when highly magnified, 

 subelliptical, adhering in clusters of 4 to 6, minutely warted 

 on the outer side, 10 to 12 /x X 8 to 9 /x diam. — Torrend Fl. 

 Myx., 84. 



PI. 193. — a. plasmodiocarp ; b. capillitium attached to fragment of sporangium- 

 wall, and clustered spores ; c. capillitium and spores ; (Norway). 



This species was found first on rotten planks at Sande, Norway, 

 September, 1894, associated with Licea flexuosa, to which it bears a 

 superficial resemblance ; D. corticatum may however be distinguished 

 in the field by the more lilac or pinkish colour of the spores. It has 

 since been obtained from Northumberland, Scotland, Sweden, 

 Austria and the Jura Mountains. Dianema corticatum holds an 

 intermediate position between the genera Dianema and Prototrichia, 



