REPRODUCTIVE ECOLOGY OF TETRAPHIS-PELLUCIDA .2. DIFFERENTIAL SUCCESS OF SEXUAL AND ASEXUAL PROPAGULES

Sexual and asexual propagules of Tetraphis pellucida differ in dispersal pattern and establishment success. In field and laboratory trials, the spore dispersal pattern was leptokurtic, but a significant fraction of the spores was trapped as far as 2 m from the colony. Gemmae were dispersed within 10 cm of the colony. The two forms of gemmiferous shoots, cupped and stalked, differed in microtopographic distribution but did not differ significantly in dispersal potential. Stalk-gemmae were positively associated with steeply sloped microsites. Gemmae were far more successful than spores in establishment of new shoots on bare substrate. Neither gemmae nor spores were capable of colonizing in the presence of established competitors. Production of gemmae facilitates local colonization of decaying stumps, whereas spore production ensures long-distance dispersal to newly available sites.