Pseudognaphalium luteoalbum

Taxonomic notes

Pseudognaphalium Krip. is a genus that needs critical evaluation as there is some suggestion that it might be better placed in Helichrysum Mill., whilst many botanists favour recognition of Laphangium Tzvelev for at least some of those plants referred to Pseudognaphalium (e.g., Greuter 2003). These generic issues aside, at the species level the New Zealand plants referred to the Northern Hemisphere P. luteoalbum (L.) Hilliard et B.L.Burtt remain problematic. New Zealand plants do not look like the type of that species and there is range of variation evident. There have been attempts to segregate that variation into informal tag name ‘units’, such as P. “coast”, P. “Kaitorete”, P. “mountain”, and P. “Zoo”. However, some of the characters used to recognise these units have proved unstable in cultivation. Further critical study is needed not only to examine the variation present in New Zealand but also the status of Gnaphalium luteoalbum var. incanum A.Rich.—proposed for New Zealand plants by Richard (1832), and accepted by Allan (1961) but dismissed by Webb et al. (1988) as part of the variation within their broad worldwide concept of P. luteoalbum. Notably neither Allan (1961) or Webb et al. (1988) elaborated on their decisions with any critical taxonomic evidence; Allan (1961) says nothing whilst Webb et al. (1988) offered an opinion. Any taxonomic study of New Zealand plants would also need to consider those Australian and Pacific plants currently referred to Pseudognaphalium luteoalbum.

Pseudognaphalium ephemerum de Lange was proposed as a new name (nomen novum) for Gnaphalium luteoalbum var. compactum Kirk (de Lange et al. 2010). That species has not been widely accepted either and requires further critical study. The problem being that the assumption by field botanists that any small, flat Pseudognaphalium growing in Eastern South Island ephemeral wetlands (on lake margins and tarns growing on mud left as waters recede during summer) is this species, is not always valid as other races of Pseudognaphalium can adopt that morphology and will grow in these habitats as well—their recognition requires cultivation. In this regard P. ephemerum s.s is best recognised as being a small plant with strict annual habits that is very difficult (if not impossible) to cultivate. Whatever its status, for now many field botanists and ecologists accept it as a valid species.

Therefore, pending further taxonomic investigation and with the exception of Pseudognaphalium ephemerum, a broad concept of P. luteoalbum is used here.