Platanthera lacera × leucophaea, a new cryptic natural hybrid, and a key to northeastern North American fringed-orchids

Abstract

To evaluate the putative hybrid origin of fringed-orchids from York County, Ontario, morphological attributes of hybrid flowers were evaluated with respect to both a random sample of herbarium specimens and populations from the hybrid location. The putative hybrids were intermediate in spur length, petal width, and vertical distance across opening to the spur as well as in eight other quantitative characters. The hybrid is named Platanthera ×hollandiae Catling & Brownell (= Platanthera lacera (Michx.) G. Don × Platanthera leucophaea (Nutt.) Lindl.). With pale greenish-white flowers, partly reflexed lateral sepals, and a horizontally linear spur opening, the putative hybrid plants resemble P. lacera but can be readily distinguished by their relatively long spurs, relatively broad lateral petals, and ovoid instead of strap-shaped viscidium. A key including characteristics of the column is included that allows the separation of all northeastern North American fringed-orchids and their known natural hybrids.Key words: orchid, hybrid, Platanthera lacera, Platanthera leucophaea, Canada, Ontario.