Morphometric analysis of Correa lawrenceana (Rutaceae) and the reinstatement of var. ferruginea endemic to Tasmania

Correa lawrenceana Hook. is a widespread species in south-eastern Australia with eight recognised varieties. The Tasmanian variety, var. lawrenceana, is morphologically diverse. The present study uses multivariate morphometrics, including cluster, ordination and canonical discriminant analyses of samples of all recognised varieties of C. lawrenceana to assess whether more than one Tasmanian form warrants taxonomic recognition. These analyses showed that (1) var. lawrenceana can be divided into two well discriminated groups that are both endemic to Tasmania, a glabrescent form from the north-east and a hirsute form from the western, central and south-eastern regions, (2) the glabrescent form matches the type of C. lawrenceana and thus retains the name var. lawrenceana, and the hirsute form matches the type of C. lawrenceana var. ferruginea Hook.f. that is reinstated. The two varieties are separated geographically except in a small area around Deloraine in the north where intermediate morphological forms occur. The density of trichomes on the abaxial leaf surface is important for distinguishing the two Tasmanian varieties. An updated key to all varieties of C. lawrenceana along with descriptions of the Tasmanian varieties is presented. Nomenclature of the Tasmanian taxa is discussed and C. lawrenceana, C. lawrenceana var. glabra Benth., C. lawrenceana var. glabra L.Rodway and C. ferruginea Gunn ex Hook. are lectotypified.