In Sanicula arctopoides, a perennial monocarp, removal of umbels, both naturally by deer (Odocoileus hemionus) and by artificial clipping early in the flowering season in California, led to no loss of maternal reproduction as measured by seed number and seed mass. Compared to controls, artificial removal of developing fruits 20 days later than the normal stage resulted in a 42% decrease in seed production. Successive clippings that removed about 55% of each plant's flowers resulted in a 52% decrease in seed production relative to controls; however, a single clipping of the same intensity resulted in full compensation. Differential reactions to clipping of different umbel ranks provided information about the mechanism of response. These responses indicated that delayed abortion of developing seeds may be common in secondary umbels, that removal of secondary umbels by herbivores may relieve plants of some costs of abortion, and that S. arctopoides uses flexible allocation to achieve full compensation at typical levels of floral herbivory.
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