Caularthron is a genus of 4 species of epiphytes found predominantly in the amazons (Colombia, Venezuela, Guiana, Brazil) and Trinidad and Tobago.

They are epiphytic orchids with highly specialized, robust, cylindrical, hollow pseudo bulbs that house ants. In exchange the plant through its leaves digests the waste produced by the ants.

The pseudo bulbs can be up to 30 cm long; the small number leaves can reach lengths up to 40 cm.

The plants bloom from late winter to spring. The inflorescence is erect and grows out of the apex of the pseudo bulbs. The numerous white and showy flowers are relative large, up to 6cm wide and fragrant.

These orchids are very difficult to obtain and therefore cultural information is scarce.

Allegedly, Caularthron prefers dry conditions and plenty of light (full sun?). It can be grown potted in medium size bark or suspended in a hanging basket. It requires warm temperatures, good humidity and watering once a wee. When it is resting during the winter requires no watering.

Be aware: As part of the Plant - Ants relationship (symbiosis or free housing agreement), the ants provide full pest control and protection to the host plant; however, the ants will continue their normal business of farming scales, mealy bugs, etc, with other plants in the area. To avoid that, keep your Caularthron plants as far away from your other orchids as practicable.


It is always wise to read as much as you can and improve your knowledge, before you buy any plants.