42 ARISAEMA TRIPHYLLUM 
occasionally through the year. Of this bunch of plants reset 
early in the season—before the flowers were formed—but three 
produced pistillate spikes the next year. 
Yet another observation must be noted here. The spring of 
1913 was peculiar in southern Indiana because of a flood condition 
in March and April (a rainfall of 14.34 inches was recorded between 
March 23 and April 30) followed by extreme drought. The 
result upon A. triphyllum was that by June 1 all plants except 
those near springs or at the margins of water-courses, were withered 
and dead. As has been stated above, the usual ratio of staminate 
to pistillate spikes is about 3:2. A careful count of plants in the 
spring of 1914 showed among those not neara water supply a ratio 
of about 70 staminate to 1 pistillate, while among plants near 
springs, in perennial marshland, and in shaded, damp ravines, the 
usual ratio held. The change in ratio in passing from the damp 
bottom of a deep ravine to the top of the side was quite noticeable. 
Along the waterway the usual number of pistillate flowers were in 
evidence, while on the upper part of the slope where growth had 
been checked by the early drought of the previous summer, only 
staminate spikes could be found. Such a difference is not usual; 
and it seems that its appearance in 1914 is in some way related to 
the short growing season of 1913. 
It has been observed that the usual ratio between staminate 
and pistillate spikes holds from year to year in limited areas with 
a non-failing or late failing water supply. This is true without 
regard to soil, as shown by colonies growing in leaf mold between 
limestone fragments, others in deep, rich loam of moist woodlands, 
and yet others in the poor, recent clay of young ravines. Plants 
do not grow with equal vigor in the different kinds of soil, but the 
difference in available food seems to influence the vegetative 
development primarily, and the sexual development little, if at all. 
One particular colony of about fifty plants growing on a steep clay 
bank, slightly shaded, but well watered by seepage from under- 
lying limestone has been observed closely. The plants average 
1.5 dm. in height, the largest specimen being 2 dm. high. The 
petioles are slender and the corms undersized, but the flower 
spikes show the usual ratio of males and females. 
One point from experimental work should be noted here. 
