PAPERS ON BOTANY 175 
This fungus is barely visible as a brick-red discoloration of 
small areas of the lower side of the leaf. The lens shows this 
color to be due to myriads of minute perithecia and pycnidia 
intermingled. 
Under the microscope the fungus appears as one of exqui- 
sitely delicate beauty. The basal wreath of hyphae marks on 
its inner side an almost exact circle. Within this circle the 
asci develop and remain together, covered by a structureless 
gelatine which when young barely reveals its origin in a loose 
network of fine mycelial threads. The perithecium is perfectly 
transparent. So transparent are all structures that the asci may 
readily be counted looking through the perithecium, either 
from above or below. 
(b) 
Fig. 4. Dexteria pulchella 
(a) Perithecium showing wreath of hyphae surrounding the asci from 
which the covering has disappeared. The rupture on one edge was caused 
by the cover glass. 
An ascus. 
(c) Spores. 1207 (type), drawn by J. MacInnes. 
Nectria Fries 
Nectria ochroleuca (Schw.) Berk. Sta. Ana, 6757. 
Creonectria Seav. 
Creonectria gramnicospora (Ferd and Wge) Seaver. On 
dead wood. Rio Piedras, (Stevenson) 3896, 6736. 
(e) 
