The nomenclatural history of Phormium colensoi Hook.f.

ABSTRACT The complicated nomenclatural history of Phormium colensoi Hook.f. is reviewed. The name and a very brief validating description, both attributed to Joseph Dalton Hooker, were published in 1848 in an article by Le Jolis. The brevity of the description does not affect the validity of the publication, and the name is here accepted as validly published. Indirect references to gatherings by Banks & Solander and by Colenso are discussed to identify original material. Plants seen during this study at localities close to those visited by Colenso have a diverse range of phenotypes, and Banks & Solander specimens also seem to show more than a single phenotype. A lectotype is therefore not designated at this time. Possible synonyms for P. colensoi are also discussed. Phormium cookianum Le Jol. is the name currently recognised by New Zealand botanists, but this has not historically always been the case. A Le Jolis specimen at Kew is designated as lectotype for P. cookianum. The possibility that P. cookianum is a provisional name, and is therefore invalid, is rejected. Phormium forsterianum Colenso is a validly published synonym, but is superfluous and illegitimate. Phormium hookeri Gunn ex Hook.f., commonly regarded as a subspecies of P. cookianum, may not be sufficiently different from phenotypes of P. colensoi to justify the same rank under that species. The conclusion by New Zealand botanists is that European writers on Phormium were greatly misled by the limited material they had to hand. An open question remains as to whether some or all the original specimens of P. colensoi and P. cookianum might be of hybrid origin. Until the necessary taxonomic work (genetic and population studies) has been done, the nomenclature of Phormium species should be regarded as an open question rather than being decided purely on publication dates.