CYTOLOGICAL STUDIES IN THE ALLIUM PANICULATUM GROUP

N the genus Alliurn there occasionally occur in nature forms with I different chromosome numbers within the same species or within a group of closely related species. In the majority of cases these then form a polyploid series, the most common case being the occurrence of diploids and tetraploids. However, triploids also occur in nature and can by means of vegetative propagation acquire a wide geographical distribution. In the Alliuzn group, which is the subject of treatment in the present paper, the paniculatum group, I have up to now found only euploid forms in nature, viz. 3 diploid species, A. paniculatum, A. pulchelluni and A. flavum, 1 triploid species, A. carinatum, and 1 tetraploid, A. oleraceum. The somatic chromosome numbers of these species are multiples of 8, the different forms thus having 2n == 16, 24 and 32 respectively. Morphologically, these species are closely related and clearly distinguished from other species of Allium, and therefore it is practical to combine them into one unit, the panicnlatum group.