Carmichaelia hollowayi

Species

Carmichaelia hollowayi

Etymology

Carmichaelia: after Carmichael, a botanist

Common Name(s)

Holloways broom

Current Threat Status

2012 - Threatened - Nationally Critical

Previous Threat Status

2009 - Threatened - Nationally Critical
2004 - Threatened - Nationally Critical

Qualifiers

2012 - CD, RF, RR
2009 - CD, RF, RR

Authority

Carmichaelia hollowayi G.Simpson

Qualifiers

CD, RF, RR

Family

Fabaceae

Brief Description

Rare low-growing shrub with many yellowish erect leafless orange-tipped branches inhabiting limestone in the Waitaki Valley. Branches 3.5mm wide, with rounded tip. Flowers small, pea-like, white with dark purple centre, in small clusters. Fruit a long-lasting sharp-tipped dry pod containing 1-3 hard olive seeds.

Flora Category

Vascular - Native

Synonyms

None

Distribution

Endemic. South Island, where it is only known from limestone outcrops on the south bank of the Waitaki River.

Habitat

Limestone bluffs, outcrops, colluvium and their associated rendzina soils.

Features

Dwarf, suckering broom, up to 0.5 x 1(-2) m. Branches 10-30 mm diam., stout, horizontal, spreading, cladodes virtually leafless, 50-80(-100) x 3.5 mm, erect to spreading, yellow-green, apex rounded, never sharp-tipped. Leaves when present, simple, 4.5-12.5 x 1.8-4.5 mm, obovate to oblanceolate, green. Inflorescence a (1-)2-3-flowered raceme, flowers dark purple. Standard 7-8 x 7-8 mm, broad-orbicular, erect, purple or red-purple, margins white. Wings 5.5-6.5 x 2.5-3 mm, oblong, white, purple veined, keel 5 x 3.5 mm, distally tinged purple otherwise white or purple-veined. Pods long persistent, 8-11 x 4.8-6 mm, broad elliptic, laterally compressed, valves very flat. Seeds 2.5-2.9 x 2.4-2.6 mm, reniform, 1(-2) per pod, yellow-green or green with black mottling.

Similar Taxa

Carmichaelia hollowayi is identified by the pod, which is conspicuously laterally compressed and by the cladode apex which is rounded rather than sharp-tipped like Waitaki forms of C. petriei Kirk and C. australis R.Br. It is one of three native brooms (the others are C. astonii G.Simpson and C. glabrescens (Petrie) Heenan) naturally confined to limestone rock and associated soils.

Flowering

November - December

Main Flower Colour

White

Other Flower Colour

Violet / Purple

Fruiting

January - May

Propagation Technique

Easily grown from fresh seed. Can also be grown by hardwood cuttings but these can be slow to take root. Plants will not tolerate humid conditions, and require a sunny, well drained, fertile soil.

Threats

There are less than 250 adult plants in the wild found in three populations. Because the species suckers, exact numbers of adult plants cannot be determined and it is likely than there are far fewer than currently believed. Although two of the three known populations occur on protected or covenanted land, the species remains at serious risk at all sites from browsing animals and from competition by tall grasses, shrubs and hawkweeds. Aside from these issues recruitment failure (in part linked to weed control) seems to be critical problem.

Chromosome No.

2n = 32

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

 

  

References and further reading

de Lange, P.J.; Heenan, P.B.; Norton, D.A.; Rolfe, J.R.; Sawyer, J.W.D. 2010: Threatened Plants of New Zealand. Christchurch, Canterbury University Press. 471pp.

Heenan, P. B. 1995: A taxonomic revision of Carmichaelia (Fabaceae-Galegeae) in New Zealand (part I). New Zealand Journal of Botany 33: 455-475.

Thorsen, M. J.; Dickinson, K. J. M.; Seddon, P. J. 2009. Seed dispersal systems in the New Zealand flora. Perspectives in Plant Ecology, Evolution and Systematics 2009 Vol. 11 No. 4 pp. 285-309

This page last updated on 19 Dec 2014

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