Slipper orchid  (Paphiopedilum hennisianum)

Slipper orchids are named for their beautiful and peculiar slipper- or shoe-like flowers (3). The flowers of Paphiopedilum hennisianum are formed from white petals with attractive bright green and purplish-red vertical stripes (2). One of the petals, called the lip, forms the slipper-like structure, and is rich purple-brown with brownish-black veins (2). The stems of this slipper orchid are purple and covered with soft and downy hairs, and each stem bears just a single flower (2). The leaves at the base of the plant are green patterned with a darker green marbling and have a distinct fold along the middle. They can measure up to 14 centimetres long and 3 centimetres wide (2).

Endemic to the Philippines, where it occurs in the Visayan area (2).

Most Paphiopedilum species grow in leaf litter or in cracks in rocks containing organic matter (3).

The colour, patterns and structure of slipper orchid flowers have all evolved to attract insect pollinators (4) (5). An insect, lured to the attractive flower, will be guided by the colourful markings and ridges to the shoe-like lip (4). The inside walls of the lip are slippery and so the only way out for the insect is via a ladder of hairs that takes the insect past the stigma where pollen is deposited (4) (5).

After pollination, the petals fade, the stigma closes up, and the ovary begins to swell. The ovary gradually develops into a green pod that turns yellow as it matures. When mature, the pod bursts open to release powdery, almost microscopic seeds that are so light they can be carried on air currents for hundreds of kilometres (4).

Wherever the tiny seeds lands, they will only germinate if a certain fungus is present. The thread-like strands (or hyphae) that make up the fungus penetrate the orchid seed and the seed then begins to digest the hyphae, thus gaining the nutrients required for growth (6).

The stunning flowers and the relative rarity of slipper orchids make them highly attractive to orchid collectors and growers (3). While trade in wild Paphiopedilum hennisianum is now prohibited, illegal collection and trade remains a potential threat (3). Due to their specific habitat requirements and dependence on a specific fungus, slipper orchids are also very vulnerable to any disturbance or modification of their habitat (6), although it is not known whether the habitat of Paphiopedilum hennisianum is specifically threatened at present.

All Paphiopedilum species are listed on Appendix I of Convention on International Trade in Endangered Species (CITES). This listing prohibits the trade in wild-collected plants, but allows trade in artificially propagated plants (3).

For further information on the conservation of orchids see:

• Orchid Conservation International:
  www.orchidconservation.org
• Orchid Conservation Coalition:
  www.orchidconservationcoalition.org

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk