THE INTERGENERIC HYBRID ORIGIN OF POA-LABRADORICA (POACEAE)

Phytogeographic, ecological, morphological, anatomical, cytological, isozyme, and endonuclease restriction site evidence is presented demonstrating that Poa labradorica is of intergeneric hybrid origin between Dupontia fisheri subsp. psilosantha (pistillate parent) and Poa eminens (staminate parent). Poa labradorica is endemic to recently deglaciated areas of northern Quebec and Labrador which are within the overlapping range of the putative parents. Incapable of sexual reproduction, P. labradorica dominates large areas of coastal marsh through vigorous production of rhizomes. Most morphological, anatomical, cytological, isozyme, and DNA characters studied in P. labradorica showed states intermediate or additive to those of the putative parents.