Morphometric Analysis of the Rattan Calamus javensis Complex (Arecaceae: Calamoideae)

Calamus javensis (Calamoideae) is a slender rattan common in tropical rainforests. The species is very polymorphic and forms a species complex together with some undetermined forms and the species C. acuminatus, C. amplijugus, C. congestiflorus, C. corrugatus, C. elopurensis, C. hypertrichosus, C. impar, and C. tenompokensis.Within the complex, themorphological variation and similarities among the entities are too difficult to solve with traditional morphological observation. Therefore, two multivariate analyses, MDS (multidimensional scaling) and hierarchical cluster analysis (HCA) with UPGMA (unweighted pair group method with arithmetic mean) were used for two datasets, quantitative data only and in combination with qualitative data. The inclusion of qualitative characters did not make significant differences in the cluster results. Of all nine taxa included in the complex, only two clusters resulted from the analysis next to two forms based on few specimens. Only C. tenompokensis was recognized as a separate cluster, while all other taxa were combined into one typical C. javensis cluster. Morematerial may result in the recognition of the two forms as distinct species.