Harris County Precinct 4 Mercer Arboretum & Botanic Gardens
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Southern Lady's-Slipper Orchid

  Southern Lady's-Slipper Orchid
 

Southern Lady's Slipper Orchid

   

Mercer Arboretum & Botanic Gardens is a member of the Center for Plant Conservation’s (CPC) National Collection of Endangered Plants, a network of botanical facilities throughout the United States and territories. The National Collection maintains the largest collection of rare plants in the world. As part of The National Collection, Mercer now banks seed and live plants for 18 species.

The southern lady’s-slipper orchid (Cypripedium kentuckiense), also known as Kentucky lady’s-slipper orchid, assigned to Mercer by the CPC in 2002, is a stunning wildflower. Joe and Ann Liggio describe this species in their comprehensive reference: Wild Orchids of Texas as "Perhaps the most spectacular of the 54 kinds of orchids in Texas." The southern lady’s-slipper orchid is one of the 50 lady’s-slipper orchid species found in Europe, Asia, and North America. This lady’s-slipper orchid has a chicken-egg-sized, cream to golden-yellow, pouch-like petal. The pouch, or "slipper," is draped by a sepal and flanked by two petals that "dangle to the sides like unfastened shoelaces." These sepals and petals range from deep maroon to yellow-green with maroon mottling. The flowers may span over eight inches. Sepals and petals are modified leaves that are attached to the male and/or female reproductive structures of flowers. In many flowering plants, the sepals often are green and the showy petals are variously colored; however, when the petals and sepals are similar in appearance, they are then termed tepals. The term Cypripedium is derived from Kypris, the Greek name for Venus and pedium for "little foot" or "slipper."

The southern lady’s-slipper orchid, the largest Cypripedium in North America, may stand over two feet tall and bears three to five eight-inch long pleated leaves that spiral up each side of the stem. This orchid inhabits isolated areas in East Texas, Oklahoma and the southeastern United States. In Texas, Cypripedium kentuckiense occurs in approximately one dozen locations and is most often found in sheltered ravines with American beech, white ash, black gum, southern magnolia, flowering dogwood, red and chalk maple, big-leaf snowbell, American hornbeam, maple-leaf and arrow wood viburnum, walter’s violet, and slender wake-robin trillium.

The cosmopolitan orchid family is one of the largest and most diverse families of plants. Orchids inhabit every continent except Antarctica. Orchids of temperate regions are primarily terrestrial (root in the ground) and range north into the arctic and to the southern tip of Argentina’s Tierra del Fuego. Most epiphytic orchids (air plants) are restricted to the sub-tropics and tropics, and grow on other plants without harming them. Epiphytic orchids possess specialized aerial roots covered in layers of spongy, water and mineral-absorbing cells.

The vine-like Vanilla planifolia is the most economically important orchid as it produces the pod-shaped fruit (capsule) from which vanilla extract is obtained. Vanilla planifolia grows in Florida, the West Indies and Central and South America. The hardy ground orchid (Bletilla striata) is a terrestrial species from China and Japan and is grown at Mercer as a perfect perennial for woodland gardens. Epiphytic orchids receive the most horticultural interest and are bred for their almost limitless diversity in form, scent, and color. Traditional orchids used in prom corsages include the Cattleya or Laelia from tropical Central and South America and the West Indies. Florists now offer Asian and Australian orchids (Cymbidium, Dendrobium), Moth Orchids (Phalaenopsis), and other species as alternatives for formal events. Many of these exotic orchids are easily grown as houseplants.

Whereas flowers typically offer gifts of pollen or nectar as food to ensure the cross-pollination by their hungry pollinators, many wild orchids offer "romantic" rewards to amorous insects. Males of specific species of wasps and bees are drawn to specific orchid flowers that mimic the females of their species. These flowers mimic the female insect in shape, color, texture, and scent. As the male insect courts one "female" after the next, they effectively cross-pollinate the flowers.

Bees and wasps in search of nectar are pollinators of Cypripedium kentuckiense, which is threatened by logging, development, and by over-collection by plant enthusiasts or collectors of traditional medicines. This Cypripedium is extremely sensitive to disturbance and as for most orchids, must grow in association with specific soil fungi in order to survive. All orchids produce minute, dust-like wind-dispersed seed that often require several years to produce flowering plants. Interestingly, some people experience an allergic skin reaction after contact with Cypripedium orchids.

The southern lady’s-slipper orchid is a unique and fragile treat for visitors to view as a spring wildflower in the proposed woodland habitat of Mercer’s Endangered Species Garden.

Anita A. Tiller, Botanist
Mercer Arboretum & Botanic Gardens
Adapted from Parkscape, Winter 2002
Photo by Joe Liggio