Description of Plates 
Bulletin 91 
Colorado Experiment Station 
PLATE I. (1) Potato plant with its subterranean parts covered by a 
dark felt-like layer of the Rhizoctcnia stage of Corticium. 
(2) A black scale-like body, or sclerotium, composed of a mass of large, 
short-segmented hyphae. 
(3) The white fruiting layer, Corticium vagum B and C, var. solani 
Burt, developing directly from the dark Rhizoctonia hyphae. 
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PLATE II. Manner of obtaining spore cultures by suspending a green 
potato stem, infected with Corticium vagum, B and C, var. solani Burt, 
over a dish containing agar. 
PLATE III. Drawings made by aid of camera lucida, material taken 
from a green potato plant. The same numbers in each case refer to the 
same thing. 
(1) Mature spore of Corticium vagum, B and C, var. solani Burt. 
(2) Sterigmata, short stalks on which the spores are borne. 
(3) Basidia, short club-like hyphae which give rise to the sterigmata. 
(4) Typical Rhizoctcnia hyphae. 
PLATE IV. Agar plate cultures. Drawings made by aid of camera 
lucida. The same numbers in each case refer to the same thing. 
(1) The spore germination at the end of twelve hours. 
(2) Growth of hyphae in two days. 
(3) Development at the end of the third day. 
(4) Development on the fifth day. 
PLATE V. Drawings made by the aid of the camera lucida. 
(1) Hyphae of Rhizoctonia stage taken from the roots of a potato plant. 
(2) Hyphae from a spore culture of Corticium vagum, B and C, var. 
solani Burt. Spores caught in potato agar and transferred to potato plugs 
on the fourth day. Drawings made on the twelfth day. The Rhizoctonia 
hyphae (No. 1) resemble those developed from the Corticium spores (No. 2) 
in every particular. 
(3) The large, short, segmented hyphae from a sclerotium taken from 
a potato tuber. 
(4) Large segmented hyphae from a spore culture of Corticium vagum, 
B and C, var. solani Burt. Spores caught in potato, agar and transferred to 
potato plugs on the fourth day. Drawings made on the twelfth day. No 
differer.ee can be observed in these (Nos. 3 and 4) hyphae. 
