104 = Self-Incompatibility in Hermaphrodite Plants 
branches which bloom later than the main ones usually omit certain of 
the earlier stages exhibited by the latter. The evidence seems con- 
clusive that when compatible cross-pollination is made there is production 
of fruit and seed in any stage except (1) and (5). The highest degree 
of self-compatibility appears to develop during the mid-season of bloom. 
‘During the latter part of the period of bloom (designated above as 
period 4) there is usually a poor development of pods and these may 
contain only partly formed seeds in which embryo abortion has taken 
place. This is evidently due to the rapid decline and death of the entire 
plant. 
Raphanus sativus. 
It can here be reported that some cultivated varieties of this species 
are decidedly self-incompatible. Nearly 50 plants of three varieties 
grown to maturity in a greenhouse have completely failed to produce 
pods to self-pollination. Of plants tested thus far only one has shown 
signs of self-fertility. It was grown in the field, bloomed from June 22 
to July 13, and produced 223 flowers many of which were selfed by hand. 
Six small pods were produced, each containing from 1 to 2 seeds. All 
these were for flowers which opened during the mid-season of bloom. 
Further studies with varieties of the radish and also of the Chinese 
cabbage are in progress. 
Lythrum Salicaria. . 
The marked sterility of this trimorphic species to self, to intra-form 
and to inter-form illegitimate pollinations was noted by Darwin (1869). 
His experiments revealed, however, that self-fertility is somewhat in 
evidence especially in the mid-styled plants. 
My own experiments with this species have thus far been confined _ 
chiefly to the growing of plants in isolation for the observation of seed 
production when subjected to free self-pollination by insects. The 
results thus far obtained show (1) that short-styled plants set very few 
pods ; (2) that long-styled plants are feebly self-fertile and that (3) mid- 
styled plants are often decidedly self-fertile. One mid-styled plant 
grown under constant observation in my own garden has shown a decided 
increase in fertility at the end of the period of bloom. All other plants 
tested have shown quite a uniform degree of self-compatibility through- 
out the entire period of bloom. 
d-season self-fertility in this species has to date been observed 
in only one plant. This condition seems to develop as an individual 
