The New Zealand Plant Conservation Network

Species

Gunnera manicata

Etymology

Gunnera: Named after Bishop Gunner, a Swedish botanist

Common Name(s)

Brazilian giant-rhubarb; giant rhubarb

Authority

Gunnera manicata Linden

Family

Gunneraceae

Brief Description

Giant rhubarb-like herb to 4 m wide or more, dying back to the large creeping stems over winter, with huge prickly leaves on erect petioles up to 2.5 m tall and large sausage-like flower spikes up to 1 m tall with tiny flowers and fruit covering the spike.

Flora Category

Vascular - Exotic

Structural Class

Dicotyledonous Herbs other than Composites

Habitat

In cultivation requires wet conditions - pond and stream margins, bogs. Seedlings sometimes appear near planted plants in NZ but have been seen 'escaped' in e.g. the Isle of Mull in 2013 (pers.obs. C C Ogle)

Features

Giant, clump-forming, gynomonoecious, summergreen herb, with short, stout, horizontal rhizomes. Winter resting buds massive, to about 25cm long. Lvs to about 2.5 m high, rhubarb-like, but rough to the touch. Petiole to 1m long, studded with conic, short, often reddish, prickles. Inflorescence spike-like and up to 1 m long, with very small flowers. small round orange fruit 1.5-2 mm long.

Similar Taxa

Very similar superficially to the much more common adventive and garden species, G. tinctoria. In the field the most obvious differences are the long narrow flower spikes of G. manicata cf. the short thick spikes of G. tinctoria. The slender radiating inflor. branches are 9.5-11 cm long in G. manicata cf. the thicker branches 4-7 cm X 5-7 mm in central part of panicle (Webb et al.1988). In G. manicata the upper leaf surface is dull green, not shiny; not or only slightly rugose or bullate (much flatter than in G. tinctoria); spines as for G. tinctoria, but much less prominent; whole surface somewhat rough but not harsh to touch. In G. tinctoria the upper leaf surface is dark green, somewhat shiny; markedly rugose and bullate; raised 'islands' between the veins bearing prominent blunt green spines with bulbous bases; sunken veins with sparse blunt yellow spines; whole surface very harsh to touch like coarse sandpaper. Separation of the two species in seedling stages seems barely possible.

Flowering

Flowering spikes longer and narrower than in G. tinctoria (see above)

Flower Colours

Green,Red / Pink

Fruiting

Each spike is capable of producing

Propagation Technique

seed; division of rhizome.

Year Naturalised

2003

Origin

Southern Brazil

Reason for Introduction

Ornamental

Life Cycle and Dispersal

As at 2016, G. manicata appears to produce seedlings infrequently in the wild and even in gardens, cf. G. tinctoria which can be prolific and a major invasive species in NZ indigenous plant communities.

This page last updated on 20 Jan 2016