Biosystematics of Hordeum bulbosum L.

Hordeum bulbosum L. is found in a diploid (2n = 14) and a tetraploid form (2n = 28). Of the 99 collections examined cytologically, 21 were diploid, 77 tetraploid and one triploid. The diploids were found in the western Mediterranean area to West Greece, tetraploids from West Greece eastwards to Afghanistan. Analysis of herbarium material and extensive cultivated material showed that the two cytotypes could not be distinguished morphologically. Intracytotype crosses were successful in the different provenance combinations, except in a few cases, where individual parental genotypes caused a low crossability. Intercytotype hybrids were rather difficult to obtain. In the light of the results a taxonomic subdivision of the species is not recommended. A problem in connection with the Linnaean type specimen is discussed.