448 AMERICAN JOURNAL OF BOTANY [Vol. 10. 



highly self-compatible (31 I no. 57), with various intervening Y ' 

 grouping of which is neither definite nor accurate. ^mens 



In these tests mid-styled plants have been more highly sen -»tOom; 

 than plants of the other forms. This is true both in relative i. t in 

 produce fruit to selfing, and in the range to higher grades of jeveral 



one plant, 31 1 no. 57, every flower that was selfed produced a \ -ctive 



other pods were produced in other flowers that spontaneous!- Sf\\ iifle 



enclosed in a glassine bag. 



Of the 97 long-styled plants tested in hand-pollinations, only 14 produced 

 pods, and not one gave over 30 seeds in any pod. In all of ^hese the self- 

 compatibility was apparently of a weak grade. 



Twenty-three short-styled plants were tested, and only one produced 

 seeds. 



The results obtained in the controlled self-pollinations with these plants 

 agree in general with those obtained in isolation tests. A rather large 

 proportion of mid-styled plants are self-compatible in some degree, and 

 nearly half of the plants of this form produced pods containing viable seeds 

 to selfing, and a few were highly self-compatible. There has been no 

 difficulty in finding mid-styled plants to use as parents of self-fertilized 

 lines of progeny. Relatively few long-styled plants produced pods to self- 

 ing, and in all such plants the self-compatibility was feeble, few pods being 

 produced and these having few good seeds. Short-styled plants have as a 

 class been decidedly self -incompatible, and of the seedlings tested only one 

 has produced seeds to selfing. The high seed-production seen in the plant 

 5 no. 1 in 1919 was not duplicated by the plant in 1918 nor in 1920 and 192 1.. 

 There has not been opportunity to test this plant by controlled hand- 

 pollinations as the plants grown from seed have been tested. 



Summary 



1. Many plants of Lythrum Salicaria are capable of producing capsules 

 and viable seeds to illegitimate self-pollination brought about either In- 

 controlled hand-pollination or by insect-pollination in the field. The 

 capacity for self-fertilization still lingers strongly in the species. 



2. The proportion of self-compatible plants is greatest in the mid- 

 styled plants, in which also the highest grades of self-compatibility are to 

 be seen. Long-styled plants are, as a class, less self-compatible, and the 

 short-styled plants are still less so. The three forms appear to differ in the 

 capacity for self-compatibility. 



3. There are wide variations in the degree of self-compatibility. In 

 the most highly self-compatible form, the mid-styled, there are all grada- 

 tions between complete self-incompatibility and the highest grade of 

 self-compatibility. 



4. The variations in the physiological condition of the sex organs, as 



