Re-interpreting the identity of the New Zealand fern Asplenium richardii Hook.f.

Abstract

ABSTRACTAsplenium richardii is a familiar and stable name that has been used for 160 years to identify an endemic New Zealand fern that occurs in montane and subalpine areas of the North and South Islands. However, re-examination of the holotype shows that it is actually a specimen of what is currently called A. gracillimum. It is shown that knowledge and interpretation of A. richardii has changed over time, and that the current concept of a montane to subalpine species is quite different to the original concept of a lowland species. This has been compounded by confusion in the identification of the type specimen. Following correct identification of the holotype, strict implementation of the Code would mean that the name A. richardii should be used for what is currently called A. gracillimum, and that the plant currently called A. richardii would require a new name. In addition, 10 different hybrids involving these two species would require new combinations. The changes would affect the floras of both New Zealand and Australia where A. gracillimum occurs. However, the Code now encourages taxonomists to avoid name changes for purely nomenclatural reasons by conserving names. It is therefore proposed to conserve the name A. richardii Hook.f. with a conserved type, thus avoiding what would be very confusing changes.