718 Transactions of the Royal Society of South Africa. 
slightly constricted, somewhat acute at the ends, oblong-ellipsoid, one cell 
slightly broader than the other, bi-guttulate when immature, 15-18 x 5-7 fc. 
On leaves of Vernonia angulifolia, Winkle Spruit, Natal, 6/7/11, E. M. 
Doidge (2511) ; Winkle Spruit, 20/5/15, E. M. Doidge (9011). 
DiMEKIUM. 
Mycelium abundant (less so in species parasitic on other Perisporiales), 
black, sub-crustaceous. Perithecia superficial, globose or ovate. Asci 
8-spored. Spores 2-celled, fuscous. 
Dimerinm intermedium Syd. 
Ann. Myc. x (1912), p. 37. 
Epiphyllous, parasitic on the mycelium of a Meliola. Hyphae very 
poorly developed. Perithecia in groups, ovate or globose, black, narrowed 
above into a papillum which terminates in a pore, 90-150 diam. Asci 
fasciculate, numerous, clavate-cylindrical, 32-38 x 8-10 ^, sessile, 8-spored. 
Ascospores distichous, sub-fusiform, 1-septate, not constricted or slightly 
so, at first hyaline, then yellow-brown, 7-10 x 3-3-5 /x, the upper loculus 
broader. Paraphyses slightly longer than the asci, filiform, numerous. 
Pycnidia similar to the perithecia but smaller, spores elliptical, one-celled, 
hyaline 2-guttulate 5*5-8 x 3-4 ^. 
Parasitic on Meliola sp. on leaves of Isoglossa Woodii, Amanzimtoti, 
Natal, 10/7/11, E. M. Doidge (1578). 
On Meliola Bhois on Harpophyllum caff rum, Kentani, 17/2/15, A. Pegler 
(8851). The spores are slightly larger in this specimen, averaging 11 
X 4 /X 
Bimerium MacOwanianum (Thuem.) Doidge. 
(Dimerosporium MacOwanianum (Thuem.), Sacc. Syll. Fung, i, p. 53.) 
Colonies epiphyllous, numerous, often confluent, black, radiating from 
the centre. Hyphae very sinuous, branched, anastomosing, warm sepia 
(E. XXIX.) 9-10 /X thick with fairly numerous alternate or unilateral 
hyphopodia, which are unicellular, globose, about 10-11 fx diam. Perithecia 
black, carbonaceous, large, up to 120 /x diam. Asci almost pyriform, 
8-spored, hyaline, with a thin wall, 75 x 50 /x. Spores clavate, bilocular^ 
Key to Species. 
A. Spores small, 7-11 X 3-4 /x. 
B. Spores 15-25 /x long. 
a. Spores 6-9 /x broad. 
h. Spores 10-13 /x broad. 
1. Spores rounded at both ends. 
2. Spores somewhat acute at each end, 
D. Gy^nnosporiae. 
D. MacOwanianum. 
D. Psilostomatis. 
D. intermedium. 
