Taxonomic studies of Australian Senecio (Asteraceae): 5. The S. pinnatifolius/S. lautus complex

Abstract

A morphological study of the Australian Senecio pinnatifolius/S. lautus complex has resulted in a revised classification for this group. Australian plants historically included in S. lautus G.Forst. ex Willd. are treated as distinct at the level of species from this and other lautusoid taxa from New Zealand. Seven new species are described, predominantly from arid or semiarid regions. These are: S. brigalowensis I.Thomps., S. depressicola I.Thomps., S. eremicola I.Thomps., S. hamersleyensis I.Thomps., S. lacustrinus I.Thomps., S. spanomerus I.Thomps., and S. warrenensis I.Thomps. Senecio spathulatus A.Rich. is recognised as a species and two new varieties are described: S. spathulatus var. latifructus I.Thomps. and S. spathulatus var. attenuatus I.Thomps. The name S. pinnatifolius A.Rich. is applied to a complex of forms occurring predominantly in mesic regions of Australia, and a new infraspecific classification is presented. Senecio capillifolius Hook.f., S. lautus subsp. alpinus Ali, S. lautus subsp. maritimus Ali, S. carnulentus var. latilobus Steetz, and S. lautus var. lanceolatus Benth. are recircumscribed and recombined as varieties of S. pinnatifolius to become S. pinnatifolius var. capillifolius (Hook.f.) I.Thomps., S. pinnatifolius var. alpinus (Ali) I.Thomps., S. pinnatifolius var. maritimus (Ali) I.Thomps., S. pinnatifolius var. latilobus (Steetz) I.Thomps., and S. pinnatifolius var. lanceolatus (Benth.) I.Thomps. respectively. Senecio pinnatifolius var. serratus I.Thomps. and S. pinnatifolius var. leucocarpus I.Thomps. are described as new. The introduced species S. madagascariensis Poir. and the native species S. condylus I.Thomps. are similar to the above lautusoid taxa and descriptions of these two species are also presented. Keys to all of the above taxa are presented.