Reproductive stems add complexity to vegetation, thereby increasing the range and quality of microhabitats available for arthropods. In this study, we evaluated whether variation in inflorescence characteristics influenced spider distribution. We compared spider guild structure among inflorescences of three herbaceous plant species, Melanthera latifolia, Conyza bonariensis and Eupatorium hecatanthum (Asteraceae), and between inflorescences of C. bonariensis in two different phenological stages, flower buds and opened flowers. Total spider abundance was higher on M. latifolia, intermediate on E. hecatanthum, and lower on C. bonariensis. Ambush spiders were more abundant on M. latifolia than on the other plant species, while the abundance of hunting spiders did not differ among plant species. Also, spiders recorded on M. latifolia were larger than those on both E. hecatanthum and C. bonariensis. However, ambush spiders were smallest on M. latifolia, while hunting spiders on E. hecatanthum were larger than on the other plant species. The number of spiders on inflorescences with flower buds did not differ from those with opened flowers, but ambush spiders on inflorescences with opened flowers were larger than those on inflorescences with flower buds. Our results with different inflorescence types support the hypothesis that differences on microhabitat structure influence distribution of spiders.