Plants of the Eloise Butler Wildflower Garden

There are two varieties of what is called the Greater Yellow Lady's-slipper and they are similar in character. The second variety - Cypripedium parviflorum Salisb. var. pubescens has larger flowers and more hair on the upper bract, and in Minnesota, it has a similar range. The larger flowered variety is extant in the Garden. This small flowered variety is not extant.

The flower stems of both can be 8 to 30 inches high and hairy.

Leaves are alternate, ovate and have prominent parallel veins and a base that mostly surrounds (clasps) the stem; leaf margins are smooth but the surface is hairy. Both stem and leaves of the Cypripedium genus can cause dermatitis.

Flowers: Members of the genus Cypripedium have three petals and three sepals, five of which are usually the same color, which can range from yellow-green to purple-brown in this species. Two sepals are joined together as to appear as one lower sepal. This joined sepal and the upper one (of the 3) form a lower and upper hood. Two petals are usually horizontal or descending, usually spirally twisted and usually purple-brown in color. The lower petal forms an inflated lip, or pouch, or slipper, which is yellow, sometimes with purple veining and with some reddish brown dots on the inside. The larger variety (var. pubescens) has flowers from 2 to 3 1/8 inches long and a pouch 1-1/8 to 2 inches long while this smaller variety has a flower that is 1 to 2 inches long with the yellow pouch from 3/4 to 1 1/8 inches long and the sepals and petals are of darker color. The pouches of both varieties may show purple veins. There is usually one but may be two flowers on an inflorescence. On the flower stem behind the flower is a green bract, resembling the leaves but smaller. The bract has a sparse amount of surface hair when young, more appearing later. The sexual parts are inside the pouch of the third petal, somewhat hidden by a the large ovoid dorsal anther of a false stamen (a staminode). There is a real anther to either side. The flowers have a sweet scent.

Seed: Pollination is usually be bees and fertilized flowers produce an ellipsoid capsule containing many small seeds, but reproduction is normally via the root system.

Habitat: Unlike the larger flowered var. pubescens, var. makasin is found in wet to moist conifer swamps, fens, wet meadows and other such areas. It tolerates sun but resists transplanting due to a symbiotic relationship with certain soil fungus called “mycorrhiza.” The root system is rhizomatous and will form a nice clump via enlargement of the root system.

Names: The former scientific name for this species was Cypripedium calceolus (L.) var. parviflorum but that is no longer accepted. The genus Cypripedium is derived from several Greek words that mean "Venus's shoe." The species name, parviflorum, is from the Latin meaning "small flower."

The authors of the accepted plant classification are as follows: For the species itself ‘Salisb.’ refers to Richard Anthony Salisbury, (1761-1829), British botanist who developed an extensive garden and published many taxonomic revisions, but much of his work was plagiarized and discredited, however some of his work has been reinstated as is the case here from 1791. As to the variety, the first to publish was ‘Farw.’ who was Oliver Atkins Farwell (1867-1944) American Botanist. His work was amended by ‘Sheviak’ who is Charles J. Sheviak, (b. 1947) American botanist and expert on the Orchidaceae family.

Varieties: There are three varieties of C. parviflorum. The variety "pubescens" (which means 'downy') is used to designate the larger flowered variety with its hairy stems, bract and leaves, compared to variety makasin, (Cypripedium parviflorum Salisb. var. makasin), which has smaller flowers and sparse hair on the bract, and which grows in swamps and bogs and was formerly present in the Garden (see historic photo below). The larger flowered variety can occur more often on upland sites, which is where it is situated in the Garden. The third variety, var. parviflorum is also small flowered, with less hair but has much more densely spotted or blotched sepals and petals and is more restricted in range into areas that are south and east of Minnesota, Iowa and Wisconsin. According to Flora of North America only this variety should be called "Lesser Yellow Lady's-slipper."