1918] 
BURT—CORTICIUMS CAUSING PLANT DISEASES 129 
dola, Ann. Myc. 1: 99. 1903; басс. Syll. Fung. 17 : 173. 1905; 
Bourd. & Galz. Soc. Myc. Fr. Bul. 27 : 248. 1911.—Rhizoctonia 
Solan. Kühn, Krankheiten d. Kulturgewüchse, 224. 1858; 
Duggar, Mo. Bot. Gard. Ann. 2: 424. 1915. 
Type: in Kew Herb. and in Curtis Herb. 
Vegetative mycelium saprophytic in the soil and in wood 
in contact with the ground, and parasitic as the Rhizoctonia 
Solani stage in underground portions of various plants and 
forming at their surface underground minute sclerotia; 
fructification a thin, arachnoid, perforate membrane more or 
: [ 4 
je WE 0А 
hypha; al, basidium; a2, spores. 6, spores of specimen on Plantago in Illinois. 
c-cl, from specimen on earth in Massachusetts. с, basidium; ci, spores. 2, 
from specimen on wood in British Columbia. d, hypha; 41, basidia; 42, spores. 
less separable, pale olive-buff to cream color; in structure 
60-100 и thick, composed of a few loosely interwoven hyphae 
running along the substratum and sending out short branches 
which bear the basidia; hyphae in contact with substratum 
may be slightly brownish, hyaline elsewhere, not incrusted, 
not nodose-septate, up to 6-10 шіп diameter, with branches 
smaller; basidia not forming a compact hymenium, 10-20» 
74-11 и, with 4-6 sterigmata 6-10 д long and more or less 
swollen towards the basidium; spores hyaline, even, flattened 
on one side, 8-14 4-6 y. 
Fructifications 5-15 em. long on logs, 5-10 em. broad; in 
a collar 1-10 em. long, sheathing the base of living stems. 
