Oct., 1923] 
STOUT-STUDIES OF LYTHRUM SALICARIA 
447 
mid-styled plant M no. 1 (see table 2). Of the 22 flowers on*it that were 
crossed during the first 18 days of bloom there were only two failures, 
the highest number of seeds for a capsule being 176 and the average 98. 
Whether such pollination would be more effective than selfing during the 
last part of the period of bloom was not tested. 
Self-compatibility Tests by the Bagging Method 
A total of about 600 plants have been grown in pedigreed cultures from 
seed. A considerable number of these have been tested for self-com¬ 
patibility in the following manner: branches were enclosed in glassine paper 
bags, and pollinations of flowers opening within were made from day to day. 
Long-styled plants and short-styled plants were selfed by using the pollen 
from mid-length stamens, and the mid-styled by use of the pollen of long 
stamens. In making pollinations, stamens with dehiscing anthers were 
removed with sterile tweezers and brushed on pistils, leaving an abundance 
of pollen. In cases of pseudo-proterogyny the fully protruding pistils of 
partially opened flowers were likewise treated along with pistils of more 
mature flowers. It appears that in the decidedly pseudo-proterogynous 
flowers the pistils protrude long before they are receptive to any kind of 
fertilization, and that highest seed production in compatible fertilizations 
occurs when pollination is made at or about the time that petals open and 
pollen is shed. On plants two or more years old, a total of as many as 500 
or more flowers were often thus pollinated. On plants in the first year of 
growth from seed the number thus selfed was often much less. 
These tests are undoubtedly less adequate than tests in isolation for 
revealing feeble grades of self-compatibility and in showing such changes in 
self-compatibility as are seen in the plant M no. 1, but hand-pollinations 
make certain that pollen in abundance is applied to the stigmas at the time 
when they are judged to be most receptive. 
The general results summarized for each form without reference to 
lines of descent are as follows: 
Fully Self¬ 
incompatible 
Feebly Self- 
compatible 
Medium Self¬ 
compatible 
Highly Self¬ 
compatible 
Mid-styled plants. 
64 
20 
21 
7 
Long-styled plants. 
83 
H 
O 
0 
Short-styled plants.... 
22 
I 
O 
0 
An attempt has been made to grade the plants according to whether the 
self-compatibility is feeble, medium, or strong, the judgment being based on 
the proportion of selfed flowers that gave pods and the number of seeds 
produced. Results typical for various grades are given in table 1. The 
tests made show that many plants of the species are without doubt entirely 
self-incompatible (M 5-7 no. 13 in table 1 for example), and that others are 
