Vessel elements and their phylogenetic significance in Blumea DC. (Asteraceae)

Vessel elements of Blumea may be broadly described as small or medium sized and with simple perforations in the more or less horizontal end walls. Intratracheal pitting consists of alternate, rounded pits, which may be regarded as highly specialized. Size variation in these tracheary cells together with the data available from other fields, has been employed to assess relative status of the investigated taxa in the process of evolution.