Cryptohybrids in Plants: Underwater Part of the Iceberg

Abstract

Interspecific hybridization is widespread in plants and is the most important factor in their evolution. For a long time, the main criterion for the hybrid origin of a plant was considered to be the morphological intermediacy of noticeable external characters. However, as the methods of chemistry and molecular biology are introduced into systematics and larger samples are studied, the researches increasingly identify the plants which are chemically and genetically hybrid, but are outwardly indistinguishable from the hypothetical parents or have an unusual combination of traits that does not allow us to recognize the hybridity and the parents by morphology.Subsequent closer study of such identified “molecular hybrids” with application of morphometry often makes it possible to find morphological, often quantitative or microscopic characteristics which confirm the hybrid nature of these plants as well. Identification and study of cryptic hybrids is important for the systematics of complex taxonomic groups with wide phenotypic plasticity, with a large number of similar species, and simplified morphology. It helps to better understand the conditions under which hybridization can occur, and is important in practical terms, especially for the control of invasive species, for the protection of rare and endangered species, etc.