OBSERVATIONS OF BOTRYCHIUM X WATERTONENSE AND ITS PUTATIVE PARENT SPECIES, BOTRYCHIUM-HESPERIUM AND BOTRYCHIUM-PARADOXUM

We observed mapped individuals of three species of Botrychium Sw. at a single site in Waterton Lakes National Park, Alberta for six years. O ur study showed that the interspecific sterile hybrid, B. xwatertonens e W.H. Wagner and its putative parents, B. hesperium Maxon & R.T. Clau son and B. paradoxum W.H. Wagner, are stable, unique genotypic entitie s. For B. hesperium and B. xwatertonense, the degree of sporophore pin nation and the number of trophophore pinnae are plastic characters wit h much of the observed variation explained by the size of the plants. Although B. xwatertonense is reported to be sterile, most sporophytes appeared more than 4 cm from other conspecifics, indicating that they are probably not produced vegetatively. Mean height of B. xwatertonens e was greater than that of either of its parents, indicating hybrid vi gor.