Phenotypic variation of leaves and stems of wild stands of Cordyline australis (Lomandraceae)

W Harris; RE Beever; PB Heenan

Abstract

To determine whether there are geographical patterns in the phenotypic variation of wild populations of Cordyline australis (ti kouka, cabbage tree), stem size, and leaf size and shape were recorded for populations at 29 locations in New Zealand ranging from latitudes 34deg.27[[minute]] to 46deg.07[[minute]]S and altitudes from 1 to 425 m. Correlations between stem and leaf variation and site and stand characteristics were examined. Stem diameter increased with increasing latitude and altitude. Leaf size dimensions and leaf shape ratios that defined differentiation of the petiole, and of leaf blade taper, also showed variation related to latitude. The phenotypic variation was predominantly continuous and followed environmental gradients that could have induced it. There was some local and regional discontinuity of phenotypic variation that was most apparent for stands in central-eastern North Island.

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