Biosystematic studies on the umbellatum-angustifolium complex of the genus Ornithogalum. (Liliaceae). II. Genome characterization and evolution

Chromosome banding techniques (Giemsa and fluorochrome staining) were used to investigate Ornithogalum umbellatum L., O. angustifolium Bor. and 11 related taxa. Nine different basic Q-banding patterns, referred to as genomes, could be recognised. These patterns are indicated by capitals (A–E, P–S). Six of the nine basic genome types can be subdivided into different subtypes. The B genome was found in the two bulbilliferous species, i.e. O. umbellatum and O. angustifolium. It occurs in a number of combinations together with the A, C, D and E genomes. Genome combinations of these five basic types were found in seven species. Six of them share morphological characteristics. These species are: O. monticolum Jord. & Fourr., O. baeticum Boiss., O. angustifolium, O. refractum, Kit., O. umbellatum and O. algeriense Jord. & Fourr. A seventh species, O. platyphyllum Boiss., in which the E genome occurs, can be regarded as an intermediate between this complex and the O. montanum group. Each species is treated extensively; its morphology, geographical distribution, chromosome number and banding patterns are discussed separately. A model of the probable course of the evolution in this complex during the last two glaciation periods is described. In this model attention is paid to ecological differentiation, migration leading to the present distribution patterns, hybridization followed by polyploidization and to fixation, which may be the result of chromosomal rearrangements that prevent regular meiosis. Some cytotypes, formerly regarded as O. umbellatum, are now classified in other species. A second polyploid complex in which these species occur, is probably more widely distributed in south-eastern Europe than is generally thought at present. The species O. exscapum Ten., O. nivale Boiss., O. comosum L., O. collinum Guss. and O. gussonei Ten. p.p. are components of this complex. The delimitation of this complex as a whole and the relationship between its diploid and polyploid components have still to be clarified.