Range and name spelling
The species occurs naturally in Bolivia and belongs to plants of seasonally dry tropical habitats. The epithet commemorates the Bolivian naturalist Belisario Díaz Romero. Leuenberger noted the spelling diazromeroana encountered in use, while POWO retains Pereskia diaz-romeroana with a hyphen. [2-WWW] [Leuenberger 2008]
Habit and flower identification
Shrubs reach about 0.5–3 m. Elongated fleshy root thickenings have been observed in cultivation. Leaves are elliptical to obovate, mostly 2–3.5 cm long and 1.2–2.2 cm wide. Spines on young twigs are usually clustered in small numbers. Small leaf size links the plant with the Andean group of the genus. [Leuenberger 1986, Pereskia diaz-romeroana description]
Pink to purplish red flowers are about 1–2 cm in diameter and develop singly or in small clusters. Long areolar hairs almost envelop young buds. More intensely coloured staminal filaments and dense hair cover distinguish the species from Pereskia weberiana. Ripe fruits are black, about 13 mm in diameter. They contain a few small seeds about 1.8–2 mm long. [Leuenberger 1986, Pereskia diaz-romeroana description]
The monograph associates the species with dry valleys of central Bolivia at about 1300–2000 m. Fruits develop within a few weeks after flowering. Recorded flowering dates come from different field collections, so they do not define a single mandatory flowering month in cultivation. [Leuenberger 1986, Pereskia diaz-romeroana description]
Seed production in cultivation
Mauseth identifies the species as self-fertile and capable of producing seeds at 2–4 years of age in cultivation. This is a useful difference from functionally dioecious Caribbean Leuenbergeria. Self-fertility means compatibility of its own pollen, and the age given is a cultivation observation rather than a guaranteed maturity date for every seedling. [Mauseth 2006]
Flowers and type material
Areoles with long hairs are visible near the flowers. Finding specimen Cárdenas 4388 in the LIL herbarium, recognised as the holotype, was important in documenting the species. Earlier, when the original material was considered lost, a specimen was designated to replace it in interpreting the name. Returning to the rediscovered holotype clarified the nomenclatural basis. [Leuenberger 2008]
Unconfirmed yellow-flowered form
Ritter mentioned a yellow-flowered plant from Bolivia, but Leuenberger found no confirming material in the collections examined. The mention remains part of research history. It has not been treated as an established variety or typical flower-colour variation of the species. [Leuenberger 2008]