Quantitative morphology of the Amelanchier agamic complex (Rosaceae) at a Maine site

We tested the power of quantitative morphology to distinguish Amelanchier taxa at a Maine site where most individuals come from polyploid agamospermous species and taxonomic boundaries are potentially obscured by hybridization. We sampled 92 individuals from seven species and one putative hybrid, 13 from a microspecies we call A. "rubra," and 15 that fit no published description (unknowns). We performed principal coordinates analysis on 20 quantitative and qualitative characters, six recognized taxa, and the unknowns. Three groups are suggested: 1) A. intermedia, A. laevis, A. "rubra," four A. stolonifera, and four unknowns; 2) A. nantucketensis and three A. stolonifera, and 3) A. canadensis and 11 unknowns. In the seat terplot of the first two principal coordinates axes, the only two species that overlap are A. intermedia and A. laevis. Discriminant function analyses indicate that A. "rubra" could be a hybrid of A. laevis and either A. nan tucketensis or A. stolonifera and do not support the hypothesis that A. intermedia is A. canadensis X laevis. The unknowns group with A. canadensis, A. laevis, or A. "rubra" and mostly do not appear to be F(1)s. Agamospermy and/or insufficient time for hybrids to establish after disturbance may explain the absence of an extensive hybrid swarm.