The New Zealand Plant Conservation Network

Species

Carmichaelia arborea

Etymology

Carmichaelia: after Carmichael, a botanist
arborea: From the Latin arbor 'tree', meaning tree-like

Common Name(s)

South Island broom, tree broom, swamp broom

Current Conservation Status

2012 - Not Threatened

Conservation status of New Zealand indigenous vascular plants, 2012
The conservation status of all known New Zealand vascular plant taxa at the rank of species and below were reassessed in 2012 using the New Zealand Threat Classification System (NZTCS). This report includes a statistical summary and brief notes on changes since 2009 and replaces all previous NZTCS lists for vascular plants. Authors: Peter J. de Lange, Jeremy R. Rolfe, Paul D. Champion, Shannel P. Courtney, Peter B. Heenan, John W. Barkla, Ewen K. Cameron, David A. Norton and Rodney A. Hitchmough. File size: 792KB

Previous Conservation Status

2009 - Not Threatened
2004 - Not Threatened

Authority

Carmichaelia arborea (G.Forst.) Druce

Family

Fabaceae

Brief Description

Shrub with many erect green branches inhabiting wetter South Island mountains. Branches green, grooved, oval in cross section. Leaves small, distributed along branches, consisting of 1-5 leaflets. Flowers small, pea-like, white sometimes with a purplish centre, in erect clusters. Fruit in a small dry pod, seed flattened.

Flora Category

Vascular - Native

NVS Species Code

CARARB

Structural Class

Dicotyledonous Trees & Shrubs

Synonyms

Carmichaelia grandiflora var. alba Kirk; Carmichaelia grandiflora var. dumosa Kirk; Lotus arboreus G.Forst.; Carmichaelia australis var. grandiflora Hook.f.; Carmichaelia grandiflora (Hook.f.) Hook.f.;

Distribution

Endemic. New Zealand: South Island (west of the Main Divide in Westland, Canterbury, Otago, and Southland; uncommon to the east of the Main Divide in Canterbury

Habitat

Lowland to montane. Inhabiting glacial moraine, river terraces, subalpine scrub, rock outcrops and cliffs, forest margins, and recently disturbed ground.

Features

Shrub, up to 2 × 2 m; sometimes suckering and forming broad patches up to 1 m tall. Branches up to 80 mm diameter, stout, ascending and spreading. Cladodes 70.0-150.0 × 1.5-3.0 mm, erect to spreading, sometimes drooping, rarely divaricate, linear, striate, compressed, green to dark green, sometimes hairy when young, glabrous when mature, apex obtuse; leaf nodes 4-11. Leaves 1-5-foliolate, present on seedlings and on adult plants, terminal leaflet larger; lamina 2.0-7.0 × 1.5 mm, obovate, broad-obovate to broad-elliptic, fleshy, green, upper surface glabrous, lower surface glabrescent, apex emarginate, base cuneate; petiole 7-11 mm long, glabrous except for a tuft of hairs at petiolule base, green; petiolule < 0.5 mm long, glabrous, light green. Leaves on cladodes reduced to scales, < 0.8 mm long, broad-triangular, glabrous, apex subacute. Stipules 0.9-1.3 × 1.0-1.4 mm, free, triangular, glabrous, apex subacute with a tuft of hairs, margin hairy. Inflorescence a raceme, 1 per node, each with 5-10 flowers clustered on upper third of raceme. Peduncle c.8 mm long, glabrous, green. Bracts < 1 mm long, triangular, pale brown, upper surface hairy, lower surface glabrous, apex acute to subacute, margin hairy. Pedicel 1-1.5 mm long, glabrous, green. Bracteoles < 0.5 mm long, on upper part of pedicel or on receptacle, pale brown, upper surface hairy, lower surface glabrous, apex subacute to obtuse and with tuft of hairs. Calyx 3.0-3.5 × 2.0-2.5 mm, campanulate, green, outer surface glabrous. Calyx lobes 0.5-1.0 mm long, triangular, inner surface hairy, appressed to corolla, apex acute. Standard 6.0-6.5 x 7.0-8.0 mm, broad-obovate, patent, positioned towards front of keel, keeled, apex retuse or obtuse with an apiculate tip; white or with a pale central blotch, veins sometimes weakly flushed red-purple; claw c.1 mm long, pale green. Wings 6.0-7.0 x 1.5-2.0 mm, oblong, longer than keel, white, apex obtuse; auricle 0.2-0.3 mm long, triangular; claw 1.8-2.0 mm long, pale green. Keel 5.0-6.0 × 1.5-1.8 mm, white, apex obtuse; auricle 0.3-0.5 mm long, triangular, white; claw 2-2.5 mm long, pale green. Stamens 4.5-5.0 mm long; dorsal filaments connate for c. ¾ of length, outer stamens free for c.0.8 mm. Pistil 5-6 mm long, exserted beyond stamens, glabrous; ovules 8-11; stigma with a ring of hairs at base. Pods 7.0-15.0 × 2.7-4.5 mm, oblong or broad-oblong, laterally compressed, erect, light grey or pale brown, both valves dehiscent at distal end; beak 2.0-2.5 mm long, in a central apical position, stout, pungent tipped. Seeds 1-3 per pod, 2.0-3.7 × 1.6-2.4 mm, broad-oblong to broad-elliptic, light brown or tan.

Similar Taxa

Carmichaelia arborea is allied to C. odorata Benth. from which it is distinguished by the shorter peduncle and rachis, fewer, larger, mostly white flowers, with keels 5-6 mm long (cf. 3.5-4.0 mm long), and larger pods.

Flowering

December - March

Flower Colours

Violet / Purple,White

Fruiting

January - December

Propagation Technique

Easily grown from seed and hardwood cuttings.

Threats

Not Threatened

Chromosome No.

2n = 32

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

Life Cycle and Dispersal

Seeds are possibly dispersed by wind and granivory (Thorsen et al., 2009).

This page last updated on 31 May 2014