Feb., 1921] 
THOM AND CHURCH — ^ASPERGILLUS 
less under such differences of environment than the primary sterigmata. 
Transfer from the corn back to Czapek's solution agar gave the original 
measurements. Such cultural experiences emphasize the necessity of 
using a standard medium as the basis of comparative studies of saprophytic 
organisms and destroy all faith in the significance of measurements to the 
fraction of the micron from miscellaneous cultures. At best a range of 
measurements must be allowed for in the most carefully standardized 
culture work. 
Cultures with this group morphology vary in shades of color enough to 
separate different strains when observed in parallel culture. A ten-day 
petri-dish culture (no. 3565) showing its outer zone maize yellow, inter- 
mediate zone ora7ige-citrine, and deepest area medal-bronze (Ridgway loc. 
cit., IV. 19 f, k, and m) was inverted over a dish of hydrochloric acid. The 
shade of mixed yellow and orange quickly changed to Saccardo's olive 
(Ridgway III, 19m). The petri-dish culture was then placed over a dish 
of strong aqua ammonia and quickly changed toward a shade between 
raw umber and Brussels brown on the same plate (Ridgway III). This 
color approximates that of very old cultures of members of this series which, 
in common with those of A. flavus, become more alkaline with age. The 
response in A. tamari is not as conspicuous as the change in green shades 
of the A. flavus group, but clearly indicates that differences in color of the 
same culture at different ages and between different strains of the series is 
due to variation in the reactions induced by the metabolic activity of the 
organism. These differences vary with the composition of the medium and 
with the characters of the race or strain studied, but clearly indicate close 
relationship among the forms. 
A. citrisporus von Hohnel. Another form having characters of this 
group was sent by Dr. Thaxter^*^ from excrement of caterpillars. In 
Czapek's solution agar cultures, this form showed colorless submerged 
mycelium, and conidial areas at first yellow, then golden, and finally fulvus; 
stalks I to 2 mm. high, up to 20 to 25 /z in diameter, turgid when young, 
often collapsing in age or when exposed to dry air, septate, with walls thin (i 
or less mostly), appearing to be studded with fine granules when examined 
directly (in air) but appearing smooth in liquid except when high magnifi- 
cation and great care are used to demonstrate the abundant pitting; with 
heads up to 500 ix in diameter ; vesicles 30 to 50 in diameter, nearly globose, 
and fertile over nearly the entire surface; sterigmata in one series, 8 to 12 }i 
by 3 to 4 w^ith long, loosely radiating conidial chains. Conidia yellow or 
golden, then brown, lemon-shaped, 5 to 9 by 5 to 6 ;u, rough from irregularly 
branching ridges of yellow to brown coloring matter between the inner and 
outer wall. 
Sclerotia are occasionally found. 
Cultures from excrement of caterpillars by Dr. Roland Thaxter. 
Culture received bore the manuscript name A. clirysospermum. 
