Gunnera × cryptica
Common names
Brazilian giant-rhubarb; giant rhubarb
Biostatus
Exotic
Conservation status
Not applicable
Category
Vascular
Structural class
Herbs - Dicotyledons other than Composites
Simplified 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. The photos on this page that bear text boxes with ‘G. manicata’ should be interpreted as meaning ‘Gunnera x cryptica’ .
Flower colours
Green, Red/Pink
Detailed description
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 Gunnera × cryptica cf. the short thick spikes of G. tinctoria. The slender radiating inflor. branches are 9.5-11 cm long in Gunnera × cryptica cf. the thicker branches 4-7 cm X 5-7 mm in central part of panicle (Webb et al.1988). In Gunnera × cryptica, 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 taxa in seedling stages seems barely possible.
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)
Detailed taxonomy
Genus
Family
Taxonomic notes
Shaw et al. (2022) have shown that all known plants in cultivation outside of Brazil, and which were previously named as G. manicata, are actually hybrids between that species and G. tinctoria
Endemic genus
No
Endemic family
No
Ecology
Flowering
Flowering spikes longer and narrower than in G. tinctoria (see above)
Fruiting
Each spike is capable of producing
Year naturalised
2003
Origin
Southern Brazil
Reason for introduction
Ornamental
Life cycle and dispersal
As at 2016, Gunnera x cryptica ppears 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.
Propagation technique
seed; division of rhizome.
Other information
Etymology
gunnera: Named after Bishop Gunner, a Swedish botanist
Referencing and citations
References and further reading
Julian M. H. Shaw*, Dawn Edwards, John David, 2022. British & Irish Botany 4(3): 364-384, 2022 A new spontaneous hybrid in Gunnera subgenus Panke (Gunneraceae) widespread in the British Isles, with notes on the typification of G. manicata
Webb, CJ; Sykes, WR; Garnock-Jones, PJ 1988 Flora of NZ Vol.3. Botany Division, DSIR, NZ