Flora of New Zealand - Gramineae supplement I: Danthonioideae

Abstract

The newly erected grass subfamily Danthonioideae encompasses four New Zealand genera viz Chionochloa, Cortaderia, Pyrrhanthera, and Rytidosperma, 43 endemic species comprise it. In Rytidosperma new chromosome counts confirm earlier reports of diploid and hexaploid species and report tetraploids (2n = 48) as an additional level of ploidy. In Pyrrhanthera 2n =, c. 156, which is the highest chromosome number in the subfamily and second highest recorded in the Gramineae. New Zealand species of Cortaderia should not be included in the same clade as South American species according to cladistic analyses of rpoC2 and ITS sequences. Morphologically this separation fails. Monophyletic Chionochloa is generically secure. Earlier data on the triterpene methyl ethers (TMEs) isolated from the epicuticular leaf wax of species of Chionochloa and Cortaderia are interpreted along modern pathways of the biosynthesis of the precursor sterols and triterpenols, and their subsequent methylation. In Chionochloa where 18 taxa in 33 synthesise TMEs mostly as single compounds, dedicated synthases for each of several triterpenoids is indicated. Non-randomness of TME synthesis is characteristic, but there is no total accord between taxonomic treatment and TME synthesis. Zones of TME-richness lie in the Tararua and Rimutaka Ranges, southern North Island (6 TMEs), and Canterbury, South Island (5 TMEs). © 2004 Taylor & Francis Group, LLC.