SEXUAL COMPOSITION OF POPULATIONS OF FRAGARIA-VIRGINIANA (ROSACEAE) COLLECTED FROM MINNESOTA AND WESTERN WISCONSIN

Populations of Fragaria virginiana Miller collected from 39 sites in M innesota and western Wisconsin were gynodioecious, in that 35% of the plants were pistillate, 65% were hermaphroditic with perfect flowers, and none were staminate, when scared for gender expression in greenhou se or field plantings. Instability of gender expression across environ ments was apparent in 15% of the collections and these genotypes that appeared to change gender were termed weak hermaphrodites. Variation i n gender composition of collections was not related in any consistent manner with the plant communities characterizing the collection sites. The proportions of pistillate plants, total hermaphrodites, strong he rmaphrodites, and weak hermaphrodites in collections from the northern forest floristic province in the northeastern part of the region were not significantly different from those of collections from the southw estern prairie-forest floristic region, although collections from the prairie-forest province were more variable for gender composition than populations from the northern forest province. Lack of staminate plan ts and increased percentages of hermaphrodite plants, relative to repo rts in the literature, suggest that the gender composition of F. virgi niana populations in Minnesota has changed, perhaps as a result of int rogression from hermaphroditic Fragaria xananassa or Fragaria vesca.