A new species of Oreomyrrhis (Apiaceae) from southern South Island, New Zealand, and comparison of its limestone and ultramafic habitats

Oreomyrrhis basicola is described as a new species from southern New Zealand. O. basicola is segregated from the O. rigida complex by its grey-green to blue-grey leaves, fewer primary pinnae, and primary pinnae that are only occasionally further divided with secondary pinnae. It is known from two base-rich habitats: ultramafic substrates in northern Southland and limestone in northern Otago These substrates have very high base saturations but differ in that the exchange complex of limestone substrates is dominated by calcium and that of the ultramafics is dominated by magnesium. O. basicola is known from three subpopulations, each with small numbers of plants, and is, therefore, considered to be Nationally Endangered.