Mar. II, 1918 Sterility in the Strawberry 623 



Richardson (jj, p. 1-6) mentioned receiving male plants of F. virgin- 

 iana from America. I have grown plants of F. virginiana illinoensis 

 from near Dresden, Ohio, which proved to be strictly diecious. The 

 literature on strawberry growing in this country during the early part of 

 the last century makes many references to the necessity of growing 

 staminate varieties for the purpose of fertilizing the pistillate forms and 

 to the fact that these plants were unproductive of fruit, but very pro- 

 ductive of plants and would soon dominate the garden if attention was 

 not paid to them. Apparently they were using staminate F. virginiana 

 plants as pollen producers. 



A study of F. virginiana in various sections of Minnesota shows that for 

 the most part this species is diecious, although some few hermaphroditic 

 plants may be found. Of a total of 1,615 pistillate flowers of this species 

 borne on 304 plants located in four distinct regions of the State, 1,180 

 set fruit, while 393 were still in the bud or blossom stage, thus indicating 

 that practically all of the flov/ers of the pistillate forms are fertile if 

 pollinated. One pistillate clone, composed of 11 plants was found, 

 however, which produced a total of 57 flowers, 18 of which were still in 

 the bud or flower stage; of the remaining 39 only one set seed. Another 

 clone of this same type was found in a different region. Material of both 

 these has been saved to test further their fertility. Plants of both of 

 these clones, when grown under conditions more favorable to pollination, 

 proved fertile. 



In contrast to the striking fertility of most of the pistillate forms is 

 the condition in the apparently hermaphroditic plants. Of 1,640 

 flowers of this type borne on 381 fruiting stalks of separate plants, 403 

 were in the flower or bud stage, while only 152 of the remaining 1,237 

 set fruit, leaving a total of 1,085 flowers which were definitely sterile; 

 286 plants of the 381 studied bore no fruit. 



The position on the inflorescence of the flowers which set is interesting 

 in connection with the problem of nubbins and pistil sterility in our 

 cultivated varieties. The fact has previously been mentioned that a 

 few flowers borne on male plants may bear only staminodia in place of 

 stamens and that these are generally fertile. Of the 152 fruits which 

 set, 31 were developed from this type of flower. The other flowers on 

 these stalks w^ere of the usual staminate form and were generally sterile, 

 although a few instances were noted in which one of the flowers bearing 

 normal stamens set a few achenes. Of these 31 fruits, 17 were borne on 

 primary, 10 on secondary, 3 on tertiary, and one on a quinary flower. 

 Five of the 152 which set were borne on flowers bearing the intermediate 

 type of anther and of these 2 were primary and 3 secondary. The other 

 flowers of these inflorescences bore normal anthers and were sterile. 

 Fifteen resulted from flowers which produced some staminodia and 

 anthers either distinctly segregated in definite portions of the flower or 

 mixed indiscriminately; of these, 12 were from primary and 3 from 



