Notes on cultivated Pereskia quisqueyana and related species (Cactaceae)

Summary: The morphological development of two seed-raised individuals of Pereskia quisqueyana Alain (Cactaceae-Pereskioideae), a Critically Endangered species, was studied in cultivation in Singapore over a period of five years and compared with other taxa from P. subgenus Leuenbergera G. Rowley. An augmented description of this imperfectly known yet evidently rather variable taxon from the Dominican Republic is provided. The genetic diversity of the species manifests itself in the presence or absence of brachyblast leaves, number and length of spines and in wide variations in the phenology of individuals grown under uniform conditions. Growth behavioural and architectural differences between P. subg. Leuenbergera (or genus Leuenbergeria) and P. subg. Pereskia are discussed and it is concluded that the former is largely acrotonic in its branching pattern, the latter mesotonic. Further notes on the morphology (including seedlings), polyembryony, geographic range, biogeography, ecology, flower insect visitors, seed dispersal, uses, specific differences and conservation status of P. aureiflora Ritter, P. bleo (Kunth) DC., P. guamacho Weber, P. lychnidiflora DC. and P. portulacifolia (L.) DC. and its Greater Antillean allies are presented, together with some observations on leaf-bearing cacti in cultivation in the humid tropics.