New Alpine Buttercup Recognised From South Canterbury and North Otago
In his 1965 treatment of the New Zealand alpine ranunculi Fulton Fisher treated two subspecies of the spectacular endemic scree buttercup R. haastii Hook.f. R. haastii subsp. haastii was regarded as endemic to the eastern, greywacke mountains of the south Marlborough and Canterbury where it inhabits fine-grained, mobile scree slopes, and subsp. piliferus F.J.F.Fisher a south Otago and northern Southland endemic of more stable rock fields and rock-slides. Recently Heenan et al. (2006) based on molecular data from two sequence regions (nrDNA ITS and cpDNA Jsa) supplemented with morphological evidence have elevated subsp. piliferus to species rank. From the conservation perspective they accept the current status for this species (currently listed in de Lange et al. (2004) as a subspecies) as “At Risk/Range Restricted”. In their paper the authors also describe as new R. acraeus which is allied to R. piliferus but differs morphologically by its finely crenate leaf and bract margins, glabrous peduncle, and in having 6-7 sepals that are hairy on the abaxial surface and glabrous on on the adaxial surface. Using the same DNA markers, R. acraeus is consistently distinguished from both R. haastii and R. piliferus. In their paper the authors suggest that R. acraeus is highly threatened due to browse from thar and chamois but argue that because at least half of the known sites are based on old herbarium records and these sites have not been recently surveyed their new species is best treated as “Data Deficient”.Fact sheets for both R. acraeus and R. piliferus are now available.
Reference
Heenan, P.B.; Lockhart, P.J.; Kirkham, N.; McBreen, K.; Havell, D. 2006: Relationships in the alpine Ranunculus haastii (Ranunculaceae) complex and recognition of R. piliferus and R. acraeus from southern New Zealand. New Zealand Journal of Botany 44: 425-441.
Posted: 18/12/2006