Lady's slipper

Family Orchidaceae. The genus gets its name from the shape of the lip, which resembles a woman's slipper. In most European languages, as in Latin, this genus is called the lady's slipper, Venus's slipper, lady's shoe, etc.

The genus slipper, or lady's slipper, includes about 50 species distributed in South and North America, Europe and Asia, from the forest-tundra to the tropics.

Plants with a rhizome, a glandular-hairy stem and large leaves. The stem is either very short, in which case there is a single pair of leaves that appear basal and a single-flowered scape, or fairly tall, with large alternate leaves and usually several, more often 1–3, more rarely 6–12 flowers.

Flowers are fairly large, of a peculiar shape, mostly brightly colored, usually with a vanilla scent. The bracts are also large and leaflike. Sepals are petaloid; the upper one is ovate or elliptic; the two lateral ones often fuse into a single, two-toothed structure at the end, directed downward. Petals are elliptic or lanceolate, hanging at the sides of the lip, sometimes more or less twisted, often colored the same as the sepals. The lip is slipper-shaped, brightly colored, variously inflated, sometimes with a longitudinal deep fold, as if split along its length or compressed in front or from the sides, with an opening or mouth at the top. The column is fused with the staminodium, on both sides of which the anthers of the two developed stamens are located. The stigma is peltate, three-lobed or triangular, turned downward into the cavity of the slipper-shaped lip. The ovary is usually not twisted, typically borne on a short stalk. Flowers are pollinated by bees.

The flowers of slippers, with their complex structure, are a typical example of "trap-flowers." Once inside the flower, pollinators—usually flying insects—can exit only by a specific route that ensures pollination. The insect is attracted by the bright color of the flower. It lands on the smooth rim of the lip, slips along it and falls into its cavity. After fruitless attempts to climb up the smooth, concave surface, the insect notices light coming from two false openings on the side walls at the base of the lip. Moving toward the light, the insect must crawl past the stigma of the flower, on which the pollen it carries is deposited, and only then can it find the real exit. Before leaving the flower it will rub against an anther and sticky pollen grains (not united into pollinia) will adhere to its body. On reaching another flower, the insect first touches the low-placed stigma and fertilizes the flower, and only afterwards the anther will dust it with a new portion of pollen.

The most ancient and most primitive genus of orchids. In plants of this genus, instead of the single stamen retained in almost all orchids, two stamens are functional and the third, underdeveloped, has become a petaloid staminodium. Pollen grains are not united into pollinia but are grouped in fours and embedded in a sticky mass.

Development of slipper seedlings from seed germination to first flowering takes about 9–10 years, and often even 13–15 years. Plants can also be propagated vegetatively by successive division of the rhizomes. Mature slippers are not overly dependent on mycorrhiza, and therefore they can be relatively easily transplanted and cultivated.

Because vegetative propagation is inefficient, and growing seedlings in sterile laboratory conditions has so far not been successful, the natural habitats of the attractive species are being plundered worldwide. As of today, the list of species grown in cultivation includes the true lady's slipper (С. calceolus) and C. macranthum (С. macranthum), as well as North American species: the showy lady's slipper (С. reginae), the small-flowered C. parviflorum (С. parviflorum), the stemless C. acaule (С. acaule) and the ram's-head C. arietinum (С. arietinum); Japanese species: C. debile (С. debile) and C. japonicum (С. japonicum); and finally the Himalayan species C. cordigerum (С. cordigerum). New slipper species still appear from time to time, for example a miniature one-leaved species that has been imported from China several times recently.

Lady's slippers lack a narrow ecological specialization, and therefore they can inhabit various biotopes, including open deciduous, mixed and coniferous forests, shrub-covered and rocky slopes, as well as meadows and heaths high in the mountains and in lowlands. Because they occur only in temperate zones of the Northern Hemisphere, their flowering mainly falls in May–July.