Relative Importance of Chasmogamously and Cleistogamously Derived Seeds of Dichanthelium clandestinum (L.) Gould

Plants of the perennial grass, Dichanthelium clandestinum, from three New Jersey populations produced ca. 10 times as many cleistogamous (CL) as chasmogamous (CH) seeds. The percentage and rate of germination were higher in CL than in CH seeds, but the percentage of potential viability, as indicated by tetrazolium chloride, did not differ for the two seed types. Percentage of emergence of seedlings, both in the field and in flats in a greenhouse courtyard, was higher for CL progeny. In a greenhouse experiment in which CH and CL seeds were sown separately or mixed in pots at three densities, there were no differences in fitness, as measured by shoot biomass and spikelet number, between CH and CL progeny. In a similar experiment involving CH and CL seedlings, there were no differences in fitness between the CH and CL progeny at any density when grown separately. However, at the lowest density of the mixtures, the CH plants were significantly heavier and had a greater number of spikelets than the CL plants.