The New Zealand Plant Conservation Network

Species

Geranium socolateum

Etymology

Geranium: From the Greek geranos 'crane', the fruit of the plant resembling the head and beak of this bird, hence the common name cranesbill.
socolateum: Chocolate i.e. 'chocolate' colouration

Current Conservation Status

2019 - Threatened - Nationally Critical

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

Authority

Geranium socolateum Heenan et Molloy

Family

Geraniaceae

Brief Description

A geranium of limestone habitats. Similar to Geranium brevicaule but differing by the more robust growth habit, longer petiole, larger leaves; these usually grey-green to light grey in colour and with a prominent brown margin up to 3.0 mm wide, and by the larger sepals and petals.

Flora Category

Vascular - Native

Structural Class

Dicotyledonous Herbs other than Composites

Distribution

Endemic. South Island, South Canterbury and North Otago.

Habitat

A species of open, sparsely vegetated, stable to semi-stable rocky limestone outcrops and associated colluvium, in a range of aspects, including open and sunny or sheltered and shaded. Also found growin amongst open prostrate shrubs and tussock-grasses.

Similar Taxa

Geranium microphyllum sens. lat. (including plants from Subantarctic Islands, South Island and North Island) differs from G. socolateum by its longer, slender, trailing stems (up to 40 cm long), open, loose, straggly growth habit; by the lack of short and compact stems and by the leaves which are broader than long, thinner and distantly placed on trailing stems. Further the basal leaves are not persistent, the infloresences bear several flowers, and these have smaller diameters (8–10 mm across) with smaller petals (6.0–9.0 mm long). Geranium brevicaule differs from G. socolateum by its more compact growth habit, smaller leaves (usually up to 20 mm diameter), polymorphic leaf colour (green, bronze, purple) but not grey-green to light grey in colour, and by its smaller sepals (4.0–7.0 mm long) and petals (5.0–7.0 mm long).

Flowering

Not known

Flower Colours

White

Fruiting

Not known

Propagation Technique

Not known from cultivation.

Threats

Heenan & Molloy (2019) note that the total population of Geranium socolateum is fewer than 1000 individuals, with the species occurring in widely scattered populations comprising a few plants. The authors note severe habitat competition from naturalised plants, and the lack of suitable habitat for recruitment suggesting that populations are declining. They recommended that G. socolateum be assessed as 'Threatened / Nationally Critical' (Criterion “B” due to the small population with a moderate ongoing or predicted decline of 50–70%). Two subcriteria also apply: (B1) 250–1000 mature individuals and (B3) total area of occupancy ≤ 10 hectares (see Townsend et al. 2008).

Endemic Taxon

Yes

Endemic Genus

No

Endemic Family

No

This page last updated on 6 Sep 2019