New Zealand Journal of Botany abstracts

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Generic placement in Lobelia and revised taxonomy for New Zealand species previously in Hypsela and Isotoma (Lobeliaceae)

P. B. Heenan

Allan Herbarium
Landcare Research
PO Box 40
Lincoln 7640, New Zealand

E. B. Knox

Indiana University Herbarium
Department of Biology
Indiana University
Jordan Hall 142
1001 East Third Street
Bloomington, Indiana 47405, USA

S. P. Courtney

Department of Conservation
Private Bag 5
Nelson 7042, New Zealand

P. N. Johnson

Landcare Research
Private Bag 1930
Dunedin 9054, New Zealand

M. I. Dawson

Allan Herbarium
Landcare Research
PO Box 40
Lincoln 7640, New Zealand

Abstract  A taxonomic revision is presented for New Zealand plants previously included in Hypsela and Isotoma , with four species recognised. The new names and combinations formally made here are all placed in Lobelia . A single dispersal event from Australia to the South Island of New Zealand is inferred to have preceded a radiation into four New Zealand species. Importantly, the four New Zealand species differ from their Australian progenitors by the capsule that is now indehiscent due to loss of the apical valves. The first species to diverge from this lineage was L. ionantha (the new name for Hypsela rivalis ), a mid-elevation species that occupies sites east of the Alpine Fault. A new North Island endemic L. carens is distinguished from L. ionantha by its usually hairy stems, leaves, and flower parts, and smaller flowers that lack purple-violet markings. The two newly named South Island species that occur west of the Alpine Fault evidently evolved from a common ancestral species that is inferred to have more narrow leaves, smaller flowers, and a reduced zone of adnation for the epipetalous stamens. One species, L. fatiscens , the name for a species previously identified as the Australian Isotoma fluviatilis , primarily occupies coastal sites, and only tetraploid plants with 2 n = 28 are known. The other species, L. fugax , is a newly described upland species endemic to the ephemeral and shallow margins of cirque lakes within Kahurangi National Park in North-West Nelson. The diploid (2 n = 14) L. fugax is like a diminutive version of L. fatiscens , which must have diverged from the common ancestral species before the chromosome doubling that occurred in the evolution of L. fatiscens . The conservation status of these endemic New Zealand species is evaluated.

Keywords  Lobeliaceae; Hypsela ; Isotoma ; Lobelia carens ; Lobelia fatiscens ; Lobelia fugax ; Lobelia ionantha ; taxonomy; phylogeny; conservation; New Zealand flora

B07027; Online publication date 26 March 2008; Received 23 July 2007; accepted 22 November 2007

New Zealand Journal of Botany, 2008, Vol. 46 : 87–100
0028–825X/08/4601–0087 © The Royal Society of New Zealand 2008

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