Arcyria. 161 



warted spores by the densely crowded spirals of the elaters, 

 and the presence of organic particles on the inner surface of 

 the sporangial wall. 



A note by Currey, who collected the specimen, now in the 

 Currey collection in the Kew herbarium, says, " The spores of 

 this specimen sown in water produced de Bary's zoospores in 

 24 hours." 



Arcyria Bucknalli, Mass. (figs. 270, 271)-1 



Sporangia sessile on a broad or narrow base, seated on a very 

 thin hypothallus, circular, reniform, or subangular from mutual 

 pressure, wall very thin, gilw-ochraceous, soon disappearing; 

 mass of spores dull orange ; capillitium well-developed, threads 

 sparingly branched and combined to form an irregular open 

 network with numerous, long, free tips, 4 5 /x thick, walls with 

 annular ridges mostly crowded, but here and there scattered, 

 and sometimes passing into a spiral, the ridges with numerous 

 thin, straight spines 3 4 ju, long the free tips irregularly swollen, 

 without spirals or rings, Imt bristling with spines, as are also 

 certain interstitial swollen portions ; spores globose, pale yellow, 

 minutely warted, 7 9 f/, diameter. 



Hemiarcyria Bucknallii, Mass., Grev., v., 18, p. 27 (1889) ; 

 Bucknall, Fungi of the Bristol district, in Bristol Nat. Soc. 

 Proc., vol. vi., pt. II., 1889, 1890, p. 4, pi. 2, f. 5. 



On wood. Bristol. 



Generally crowded, about *5 mm. diameter, but extending 

 to 1'5 mm. when isolated and elongated. Most closely allied 

 to Hemiarcyria Wigandi, Host., but. at once distinguished by 

 the larger sporangia, the markings on the elaters being mostly 

 rings and not spirals, and in being furnished with numerous 

 spines. The present species combines the characters of Rosta- 

 fmski's genera Hemiarcyria and Cornuvia, the spirals on the 

 threads of the capillitium pointing to the former, and the 

 numerous free arms to the latter. The spirals technically 

 separate this species from Ophiotheca as understood in the 

 present work. 



