The Catasetum are a strange group of orchids. There are 130 described species, but for years the plants confounded the experts. Even John Lindley who first set out to standardize the terminology and systematically classify the orchids, was confused by the Catasetum. The plants are pretty much the same in appearance; the flowers defy normal behavior.

The inflorescence arises near the base of the pseudobulb of the Catasetum. The flower may be imperfect, either staminate (male) or pistillate (female). Or the flower may be perfect (contain both stamen and pistil). The inflorescence may have all flowers of one sex or may be mixed.

The showy lip petal is usually the top petal in orchids. But most orchid flowers twist through 180 degrees, so by the time the flower is open, this showy petal is downward. This twist is called resupination. The male flowers of Catasetum tend to be resupinate, showy lip down. The female flowers tend toward non-resupination, showy lip upward.

To make identification even more difficult, the male and female flowers do not look anything alike. That is what Lindley and his fellow botanists faced--lots of Catasetum plants with all sorts of flowers, males and females and hermaphrodites looking like different species.

Orchids keep all their pollen together in neat little packets called pollinia. The male and hermaphroditic flowers have pollinia. The pollinia has an adhesive. When a bee or fly visits the flower, the pollinia is glued to its head or back to be carried to the next flower.

The Catasetum go a little further than just gluing the pollinia. They are pollinated by bees in the genera Euloglossa, Euplusia, or Eulaema. When a bee lands on the Catasetum flower, it gets shot by the pollinia.

When I was taking the above photograph, the flower was thought to be pistillate. I felt the pollinia hit my fingernail. It was firmly attached and took soap and a soft brush to completely remove the adhesive. The flowers were one of the hermaphroditic forms.

Klehm Growers has posted a photograph of the male flowers of Catasetum discolor. To view the photograph, click on the link:

http://www.klehmgrowers.com/Catasetum_discolor.jpg

The American Orchid Society has a great article on the Catasetum and how to cultivate these oddities. To learn more about the fascinating Catasetum, click on the link:

http://www.theaos.org/publications/bulletin/issues/oct99/catasetum.html