Orchidaceae — Earth’s Most Beautiful Orchids

Paphiopedilum -- Venus slipper

Paphiopedilum — Venus slipper

Paphiopedilum, often called the Venus slipper, is a genus of the lady slipper orchid subfamily Cypripedioideae of the flowering plant family Orchidaceae. The genus comprises some 80 accepted taxa including several natural hybrids. The genus is native to Southeast Asia, the Indian Subcontinent, southern China, New Guinea and the Solomon and Bismarck Islands.

Paphiopedilum species naturally occur among humus layers as terrestrials on the forest floor, while a few are true epiphytes and some are lithophytes. These sympodial orchids lack pseudobulbs. Instead, they grow robust shoots, each with several leaves; some are hemicryptophytes.

The leaves can be short and rounded or long and narrow and typically have a mottled pattern. When older shoots die, newer ones take over. Each new shoot only blooms once when it is fully grown, producing a raceme between the fleshy, succulent leaves. The roots are thick and fleshy. Potted plants form a tight lump of roots that, when untangled, can be up to 1 m long.

Members of this genus are considered highly collectible by orchid fanciers due to the curious and unusual form of their flowers. Along with Cypripedium, Mexipedium, Phragmipedium and Selenipedium, the genus is a member of the subfamily Cypripedioideae, commonly referred to as the “lady’s-slippers” or “slipper orchids” due to the unusual shape of the pouch-like labellum of the flower.

The pouch traps insects seeking nectar, and to leave again they have to climb up past the staminode, behind which they collect or deposit pollinia. Orchids of this genus are notoriously difficult to propagate by tissue culture; as of 2016, commercial cultivation is almost exclusively seed-based. This means every plant is unique.

Members of this genus have unusual stomata. Whereas most land plants’ stomata have guard cells with chloroplasts in their cytoplasm, Paphiopedilum stomata do not. This difference results in simpler, but weaker control of stomatal function.

For example, most plants close their stomata in response to either blue or red light, but Paphiopedilum guard cells only respond to blue light. The fact that they lack chloroplasts has made them valuable to researchers investigating stomatal function.

Paphiopedilums can be grown indoors, as long as conditions that mimic their natural habitats are created.

Most species thrive in moderate to high humidity (50–70%), moderate temperatures ranging from 13 to 35 degrees Celsius and low light of 12,000 to 20,000 lux. Modern hybrids are typically easier to grow in artificial conditions than their parent species.