The 'Senecio aff. lautus' Complex (Asteraceae) in Australia. I. Criteria for Exclusion of Lautusoid Senecio of Australia from S. lautus sensu stricto of New Zealand

Abstract

Criteria for reliably separating, at the species level, specimens of the lautusoid complex of Australian Senecio from the superficially similar Senecio Iautus G. Forst. ex Willd. of New Zealand are presented. This separation is based primarily on differences in the calycular bracteoles and phyllaries. S. lautus has numerous broadly lanceolate calycular bracteoles inserted on the dilated receptacle and which are tightly imbricate, with flat phyllaries lacking prominent raised ribs. Australian lautusoid specimens have fewer and narrower lanceolate bracteoles which are not imbricate, arising in a tight spiral below the dilated receptacle, with prominently bi-ribbed phyllaries. The name S. pirmatifolius A. Rich. is perhaps best applied to Australian members of this complex.