354 Gates. 
certain other species which I have not studied, such as O. missouriensis 
Sims, the color pattern on the sepals seems to consist of irregularly 
scattered red spots rather than bands of color advancing or retreating 
from the median ridge. 
The cause of the definite nature of the color pattern variability 
in such forms as O. rubrinervis seems fairly evident. The median 
longitudinal ridge of the sepals contains a vascular bundle, which is 
Fig. 2. Buds of pure O. grandiflora Ait. from Alabama, photographed natural size 
with a ray filter like Fig. 1. 
the source and distributing center for the food supply of the sepal. 
Current views of anthocyan production will be referred to later, but 
it may be mentioned here that one view considers an accumulation 
of sugars to be necessary for its appearance in any part of the plant. 
The supply of these or other materials coming through the vascular 
bundle in the median longitudinal ridge of the sepal, naturally causes 
the production of anthocyan first in the regions adjacent to this bundle, 
which therefore acts as an irrigation system. The greater the supply 
