New Zealand Journal of Botany abstracts
Flora of New Zealand – Gramineae Supplement I: Danthonioideae
H. E. Connor
Department of Geography
University of Canterbury
Private Bag 4800
Christchurch, New Zealand
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).
Keywords New Zealand; grasses; danthonioids; Chionochloa;
Cortaderia; triterpene biosynthesis; triterpene methyl ethers;
geography; taxonomy; Pyrrhanthera; Rytidosperma; nomenclature;
cytology
B04004; Received 30 January 2004; accepted 5 July 2004; Online
publication date 9 December 2004
New Zealand Journal of Botany, 2004, Vol. 42: 771–795
0028–825X/04/4205–0771 © The Royal Society of New Zealand 2004
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