Hybrids and the Flora of Thailand revisited: Hybridization in the South-East Asian genus Cryptocoryne (Araceae)

ABSTRACT. The South-East Asian genus Cryptocoryne has been shown to hybridize more frequently than expected. Data are presented on the known naturally occurring hybrids including information on their discovery, naming, and recognition as hybrids. Many artificial hybrids produced over the years indicate that there are only relatively few barriers to crossing. A heterosis effect is prevalent in many encountered Cryptocoryne hybrids. Vegetative propagation is clearly an advantage in the establishment of hybrid populations and also in detecting the hybrids, since inferior hybrids have disappeared naturally. Our results on Cryptocoryne also suggest that when the South-East Asian floras become as well-known as temperate ones, the number of natural hybrids will be similar to those presently known from temperate regions.