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Gunnera L.
Linnaeus, Syst. nat. ed. 12: 587, 598 (1767).
Literature. Schindler 1905.
Gunnera magellanica Lam. map
Lamarck, Encycl. 3: 61 (1789).
D Ildlandgunnera. N krypgunnerusblad. S krypgunnera.
Hemicryptophyte. Perennial, dioecious, stoloniferous, ± mat-forming herb. Stolons 5-10 cm, glabrous or slightly hairy, apically ascending and covered by large, cap-like, scarious, brownish ochreas; new stolons developing from leaf axils. Leaves alternate, crowded towards the shoot apices; petiole 5-10 cm; blade reniform, undulate, crenate, 1-6 × 4-13 cm, glabrous above, hairy along the veins below.
Flowers numerous, inconspicuous, in axillary, compound spike-like racemess. Male flowers apetalous; sepals 2, c. 8 mm, narrow, acute, persistent; stamens 2, with filiform filaments; anthers ellipsoid, apiculate, c. 2 × 1 mm. Female flowers (not seen in Nordic material) epigynous, sessile or short-pedicellate; sepals 2, narrow, apetalous; styles 2, narrow. Fruit (not seen in Nordic material) a drupe, c. 5 mm, subglobose or obovoid, bright red. - Mid-summer to late summer.
[2n=18].
Distribution and habitat. Sometimes grown for ornament; planted before 1960 at a pond in a park in S Klm Oskarshamn, expanding vegetatively on damp, trampled and mown ground and into adjacent pine woodland.
Along the South American Andes from Patagonia north to Colombia.
Biology. Dioecious, wind-pollinated; bird-spread in its native area, but propagated exclusively by stolons in the single Nordic locality (only male plants). - The genus Gunnera is characterized by symbiosis with cyanobacteria of the genus Nostoc, which form blue-green colonies inside the stems. Their assimilation of nitrogen is thought to help the plants to colonize mineral-deficient soils.
Comment. Gunnera manicata Linden ex André André (D Mammutgunnera, N kjempegunnerusblad, S jättegunnera) and G. chilensis Lam. (G. tinctoria (Molina) Mirb.; D Farvegunnera, N chilegunnerusblad, S röd jättegunnera) are perhaps more often grown as ornamentals. Both are perennial, rosette-forming plants with huge, rhubarb-like leaves. They are known as vigorous garden escapes in the British Isles.
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