Discocactus

The most beautifully scented cactus in the world

Discocactus is a group of species from central South America. It is disc-shaped with beautiful flowers emerging from a woolly ‘hat’, the cephalium. The disc-shaped form does not get higher than 8 cm and no wider that 25 cm. Discocactus heptacanthus varies considerably both in the wild and in cultivation.

The long white flowers open at night and smell very fragrant; some specialists believe this to be the most beautifully perfumed cactus in the world. These cacti are pollinated by pintail butterflies, which use their long proboscis to reach the nectar deep inside the flower funnel. Discrete groups of catci all flower simultaneously . How they time their flowering to coincide is not known, but it serves to increase the chance of cross pollination.

Ecology and habitat

Discocactus heptacanthus is distributed in the border region between Brazil and Bolivia, and Paraguay, in the low rocky hills of the Mato Grosso. A savannah vegetation, the cerrado, dominates this region with Discocactus heptacanthus growing in the shade of dispersed trees and bushes. The ground is derived from weathered rock that has formed sand or gravel and is often ferruginous.

Threat

Discocactus heptacanthus is fairly widely distributed but only in small dispersed groups. Over the past decade the species has declined by 25%. This reduction is due to deforestation for mining, cattle ranching and increased urbanisation. The decline is set to worsen as cattle farming and the population increase. Pollution from the mining of iron ore also plays a role. In Brazil Discocactus heptacanthus sub species melanochlorus is partly protected in the Chapada dos Guimarães National Park.