Variation in achene weight in Aster acuminatus

Abstract

In the forest understory herb Aster acuminatus, achene weight varies approximately 1.4-fold among achenes collected from single flower heads and 2.5-fold among achenes collected from numerous plants from three field sites. Inner and outer achenes in one flower head are normally similar in weight. Achenes collected from different flower heads on one plant usually vary significantly in weight. Significant variation in achene weight among plants from one patch was always observed. Variation among patches and field sites was small. Taller plants as a group had slightly heavier achenes than shorter plants. Lighter achenes were less likely to germinate and survive than heavier achenes and produced significantly smaller seedlings. The patterns of variation in achene weight indicate that most of it is nongenetic. The variation may be a consequence of short-term environmental variation during the time of achene maturation.