Cytoevolutionary Studies in the Genus Bulbine Wolf (Liliaceae) .I. The Australian Perennial Taxa (B. bulbosa s.1.)

Abstract

A cytological survey, using root tip mitotic cells, and supplemented by limited breeding and pollen fertility studies, was carried out on plants of 69 populations of the Australian perennial Bulbine bulbosa s.1. (Liliaceae). The populations are shown to fall into three main groups. The bulbosa group, characterised by the presence of a bulbous tuber, occurs at 4x, 8x and 12x levels, with somatic counts of 2n = 24, 48 and 72 respectively. The 4x bulbosa populations, which are functionally diploid, are disjunct and confined to mesic areas; the 8x and 12x populations occupy the intervening and less mesic sectors of the bulbosa range. The rock lily group has a count of 2n = 46 and is karyotypically, morphologically and ecologically distinct from the bulbosa group. A third group, represented by a single Queensland sample from the Kroombit Tableland, shares the chromosome number and habitat type of the rock lily but differs from it both morphologically and karyotypically. B. bulbosa, as currently circumscribed, is therefore considered to include at least three good species. The 4x bulbosa group, the rock lilies and the Kroombit taxon are all judged, on karyotypic and distributional grounds, to be palaeopolyploids. The 8x and 12x bulbosa forms appear to be neopolyploids or possibly, in some cases, mesopolyploids.