The pink lady's slipper orchid (Cypripedium acaule Aiton.) is one of the more common orchid species in the Great Lakes region, occurring in habitats ranging from dry sandy upland woods under mixed oaks, pines, or aspens to lowland bogs amidst sphagnummoss and beneath cedar, spruce, or tamarack (Voss, 1972; Luer 1975; Case, 1987). The plant also ranges over much of eastern North America (Case, 1987; Cribb, 1997). Variants of the plant have been recorded throughout its range, including plants with twoflowers per inflorescence and a white flowered variant (Cribb, 1997). The white flowered variant of the pink lady's slipper (f. albiflora Rand Redfield) is a rare find and typically occurs in the northeastern part of the plant's range (Luer, 1975). This variant is not a true albino or achlorophyllous plant because it contains chlorophyll and derives most of its energy through photosynthesis. Achlorophyllous plants are thought to lack chlorophyll and other pigments that are associated with photosynthesis (Cum-mings Welschmeyer, 1998). However, Cummings and Welschmeyer (1998) found in their study of ten apparent achlorophyllous plant species, representing four families (Lennoaceae, Monotropaceae, Orchidaceae, and Orobanchaceae), that chlorophyll andother chlorophyll-related pigments were present although, at dramatically reduced levels. Although no previous record of a seemingly achlorophyllous pink lady's slipper is known (Fred Case, personal communication, 20 October 2005), the purpose of this article is to announce the discovery of two separate occurrences of apparent achlorophyllous variants of pink lady's slipper in Wisconsin.
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