Dorstenia gigas bullata

Origin

Dorstenia gigas Schweinf. ex Balf.f. is endemic to the island of Socotra in the Arabian Sea, a UNESCO-recognised biodiversity hotspot belonging politically to Yemen (Africa / SW Asia). It was first collected during nineteenth-century botanical surveys of Socotra and has since become an icon of the island's succulent flora. The bullate leaf form traded informally as 'bullata' represents a particular leaf-texture variant selected from wild-collected seed and is propagated by cuttings rather than seed.

Habitat

In its natural environment, this species is a specialist of windswept limestone plateaus and granite cliff faces of the Socotran archipelago, where it grows in shallow pockets of mineral soil at altitudes around 300–900 meters above sea level. Rainfall is low and irregular, influenced by both the summer Indian Ocean monsoon and the winter trade winds, and the air stays relatively humid for much of the year. Plants perch in exposed positions where their caudices are kept cool by constant air movement.

Description

Dorstenia gigas is the largest of the Socotran succulent Dorstenias, a pachycaul species with a bottle-shaped trunk and a relatively small leafy crown that has become a holy-grail caudex plant in serious collections.

Caudex & Stem: The trunk is a swollen, bottle- to dome-shaped, smooth greyish-green caudex that can reach a metre or more in great old plants, often branching from the base and forming small candelabra-like clusters over decades.

Roots: A coarse root system emerges from the base of the caudex, anchoring the heavy stem into the thin layer of mineral soil that sits over Socotra's limestone and granite bedrock.

Leaves: Leaves are clustered at the branch tips, obovate, and in the bullate form the blade is conspicuously puckered and dimpled between the veins, giving it a crinkled, almost quilted texture. They are mid-green and somewhat fleshy, and are shed during prolonged dry periods.

Flowers & Fruit: The inflorescence is the characteristic Dorstenia shield: a flattened, irregularly lobed green disc that sits on a slender stalk above the foliage. Tiny fruits develop on the surface of the disc and are ejected ballistically when ripe.

Cultivation: Grow in a very sharply drained, mineral-rich mix under bright light and good air movement. Water moderately during warm months and keep the plant on the dry side in winter, with temperatures that never approach freezing. Specimens branch and develop character slowly, so patience is essential.