Herbarium data reveal an association between fleshy fruit type and earlier flowering time

Herbarium phenology data were evaluated and then applied in a phylogenetically independent contrast study in which flowering times were compared between fleshy and nonfleshy-fruited plants growing in the north-temperate provinces of Uppland and Sodermanland, southeastern Sweden (59 degrees - 60 degrees N). To evaluate herbarium phenology data, flowering-time information taken from herbarium specimens in the Swedish Natural History Museum ( S) was compared with two independent field phenology data sets. Herbarium collections and the field studies were restricted to the province of Uppland. Flowering times derived from herbarium specimens correlated equally well with each of the two field-phenology data sets as the field phenology data sets did to each other. Differences between flowering times derived from field and herbarium collections were not affected by the number of herbarium specimens used. However, these differences in flowering times were affected by flowering season such that herbarium-derived flowering times were later for early spring-flowering species and earlier for late summer-flowering species when compared with flowering times derived from field data. In the phylogenetically independent contrast study of mean flowering times in fleshy-compared with nonfleshy-fruited plants, herbarium data were compiled for 77 species in 17 phylogenetically independent contrasts. Flowering time was found to be earlier for fleshy-fruited taxa, illustrating the evolutionary interdependence between flowering and fruiting phases and the constraining effects of a north-temperate climate on phenology evolution. This study shows that herbaria are reliable and time-saving data sources for comparative phenology studies and allow for studies at large phylogenetic and geographic scales that would otherwise be impossible.