Discovery of a Possibly Relict Outbreeding Morphotype of Sparrow's-egg Lady's-slipper Orchid, Cypripedium passerinum, in Southwestern Yukon

Résumé

An outbreeding morphotype of Cypripedium passerinum with separate anthers and stigma was discovered in the Beringian region of southwestern Yukon. The occurrence of this breeding system in Beringia is attributed to the persistent advantage of outbreeding over hundreds of thousands of years in this unglaciated area, whereas the widespread occurrence of exclusively self-pollinating races elsewhere in Canada is attributed to advantages in colonization of recently deglaciated territory which first became available less than 10,000 years ago, and/or to a changing and more forested habitat.