90 A Monogrcqyh of the Myxoriastres. 



fragile, blackish cortex ; capillitium dense, forming an irregular 

 network, the two branches forming the angles of the larger 

 dichotomies connected by a membrane; spores brownish-violet, 

 globose, minutely Avarted, 14 — 17 ju, diameter. 



Amaurochactc atra, Rost., Mon., p. 210, fig. 67 ; Cke., Myx. 

 Brit., p. 52, f. 67; Sacc, Syll., vii., no. 1375. 



On wood and bark, especially of pines. Britain (Ascot, 

 Lyndhurst, Leicester, Somerset, Aboyne, N. B.) ; Germany ; 

 France ; Sweden ; United States. 



Varying from 1 — 3 in. or more across. 



In the typical form the sporangia are very irregular and have 

 nearly lost their individuality, whereas in other specimens the 

 whole structure suggests the idea of a number of confluent 

 individuals of a sessile Stcmonitis. 



Brefeldia, Rost. 



Aethalium composed of numerous naked, elongated, closely- 

 packed sporangia, arranged in several strata; columellas of the 

 various sporangia coalescing to form tree-like branchings, 

 branches of the capillitium meeting at the boundary of 

 the sporangia and coalescing by the formation of polycellular 

 vesicles. 



Brefeldia, Rost., Mon., p. 212; Cke., Myx. Brit., jd. 53; Sacc, 

 Syll, vii., p. 402 ; Raunk., Myx. Dan., p. 96. 



Like Bcticularia, the one species constituting the present 

 genus is only known in the aethalioid form, and the component 

 sporangia are much contorted. The principal feature of the 

 genus is the presence of numerous very peculiar structures met 

 with scattered at intervals in the threads of the capillitium. 

 These bodies usually consist of eight cell-like vesicles more or 

 less quadrate in outline, measuring 8 — 15 /u, in diameter, and 

 arranged in a quadrate manner, the capillitium threads are 

 attached to the four cells forming the two ends of the cluster 

 of vesicles by short branches, usually four in number, one 

 being attached to each vesicle. Rostafinski says that these 



