Origin.

The genus as a whole appears to have had its beginnings in the Himalayan foothills, and drifted thence into Malaya and Australia. The Australian forms probably became isolated very early,

and have differentiated independently. The Malayan forms evolved along a rather more elaborate line, passing S.E. through New Guinea to New Zealand and missing Australia entirely. Of the 7 New Zealand species, 3 belong to the Australian group and 4 to the Malayan. Two of the former group (C. aconitiflorus and C. unguiculatus) were most probably windborne originally, across the Tasman, while the third (C. carsei) is an endemic species derived from C. unguiculatus.