ENDOTHIA PIGMENTS 
339 
from the bark and extracting the mass with alcohol. The curves of 
spectral transmission of these extracts are included in figures 3 and 5. 
From the curves shown in figures i to 3 it is noticeable that the 
transmission spectra of the acidified alcoholic extracts of pure cultures 
of the species of Endothia studied group themselves into three classes. 
/ 
s 
/ 
G 
-y 
/ 
4- 
F 
s 
so 
"^40 
'^lO^-ZO A40 '^O £00 320 St-O S60 £30 GOO 620 640 660 630 700 720730 
Fig. 2. Curves of percentage of spectral transmission of acidified alcoholic 
extracts from pure cultures on rice of E. fluens (F), E. gyrosa (G), and E. singularis 
(S). The curves were plotted with the percentage ot light transmitted as ordinates 
and the wave-lengths of light in [xii as abscissae. 
The first of these includes E. parasitica, E. longirostris, and E. fluens 
mississippiensis. The curves for these three fungi agree rather closely 
in most cases, the region of greatest variation being in the shorter 
wave lengths transmitted. The distinctive feature of these curves is 
that they indicate that practically all the violet rays are absorbed. 
Only a small portion of the blue is transmitted while most of the 
yellow, orange and red rays pass through. 
The curves of spectral-transmission for E. fluens, E. singularis, and 
E. gyrosa make up the second group and are shown in figure 2. An 
inspection shows that the greatest variation in these curves is again in 
