Biology of Trillium nivale (Liliaceae)

Abstract

Trillium nivale Riddell exists in restricted populations that often are composed of many individuals. The species is primarily calciphilic, and its range is mostly within the limits of previously glaciated territory. At the study sites in central Ohio reproductive maturity usually is attained by plants 3–4 years old. Individuals of T. nivale live to be at least 8 years old; maximum longevity has not been determined but is probably considerably longer than 8 years. Meiosis and tetrad formation occur in July and August; preformed pollen in buds with relatively mature floral organs overwinter, and flowering occurs in late February through March of the next spring. Seeds mature in ca. 3 months after fertilization; an elaiosome is produced on each seed and the diaspores are disseminated by ants. Germination apparently occurs in early spring at least one season after seed production. Clonal growth is of limited importance; rhizomes very rarely produce offsets by lateral budding. Individuals of T. nivale are self-compatible, weakly protogynous, and facultatively xenogamous. We report n = 10 as the chromosome number in contrast to a previously published count of n = 12.