A new diploid form of Haynaldia hordeacea Hack.

P. SARKAR

Botanical Institute, University of Montreal, Montreal, Canada

The genus Haynaldia has been assumed by various workers to be closely related to the other genera of the Triticinae. However, the only species that has been extensively used in hybridization work, namely H. villosa, shows little chromosome homology with any species of the other genera. Besides H. villosa which is an annual and diploid with 2n=14, one other species, H. hordeacea, is known in this genus which is perennial and tetraploid with 2n=28. Morphologically the two species are quite close and both are self-sterile. Regarding natural habitat, both are known to grow in dry limy places. The area of distribution is more definitely known for H. villosa which is a native of the Mediterranean region and in its eastern limit goes as far as Caucasia and Asia-Minor. The extent of geographical range of H. hordeacea, on the other hand, is mostly unknown.

Recently, from a 1954 collection of H. hordeacea by G. L. Stebbins in Morocco, the present writer has isolated both a tetraploid and a diploid form. Both these forms are perennial, the diploid form being slower in growth than the tetraploid one and also with less coarse leaves. Meiosis has been studied in the tetraploid form and the data are given below.

The occurrence of up to six quadrivalents in a cell may indicate an autoploid derivation of the tetraploid H. hordeacea and, in that case the newly isolated diploid form is the most likely ancestral type.

Further morphological and cytogenetical studies of these two forms and also of H. villosa are now under way.

(Received Sept. 17, 1957)