Epiphytic orchids, those that grow upon a support, have modified aerial roots that can sometimes be a few meters long. In the older parts of the roots, a modified spongy epidermis, called a velamen, has the function of absorbing humidity. It is made of dead cells and can have a silvery-grey, white or brown appearance. In some orchids, the velamen includes spongy and fibrous bodies near the passage cells, called tilosomes.
If your Catasetum orchid leaves begin to yellow and drop off, do not despair; this deciduous orchid loses its leaves naturally during winter dormancy. There is much variation in appearance between Catasetum species, but one feature they all have in common is the trait of producing male or female flowers, which bear little resemblance to each other. The male flowers have an anatomical trigger that forcefully ejects pollen onto visiting bees.
Orchids of all types have also often been sought by collectors of both species and hybrids. Many hundreds of societies and clubs worldwide have been established. These can be small, local clubs, or larger, national organisations such as the American Orchid Society. Both serve to encourage cultivation and collection of orchids, but some go further by concentrating on conservation or research.