In large numbers at a few sites in Tristan: locally in the Patches, at Sandy Point and at Stony Hill [1].
At all sites associated with human activity (agriculture, and tree planting) [1]
Locally dominant [1]. Not considered alien by Roux et al (1992) and Groves (1981). Considered alien by Wace & Dickson (1965), and Gremmen c.s. (2009).
First collected on Inaccessible by Christophersen in Feb 1938. Most abundant at Blenden Hall. Smaller patches at the huts at Waterfall Beach and on the steep seaward slope between Joe's Hill and South Hill. On the plateau only in the rivervalley above Waterfall Gulch, between Round Hill and Denstone Hill. Seeds were found commonly on the Waterfall Beach plants [3]. Moseley (1984: 380) mentions a Concolvulus that was very abundant on cultivated ground near the hut of the Stoltenhoff brothers. There are no specimens of this plant, but it seems likely that these plants actually were Calystegia sepium (Groves 1981: 368).
[1] Gremmen, N.J.M. and R.L. Halbertsma (2009). Alien plants and their impact on Tristan da Cunha. Report Data-Analyse Ecology, Diever, NL.; [2] Gremmen, N. J. M. (2010). Alien vascular plants of Inaccessible, Nightingale and Gough Islands (Tristan da Cunha Group).; [3] Roux, J.P., Ryan, P.G., Milton, S.J. and Moloney, C.L. (1992) Vegetation and checklist of Inaccessible Island, central South Atlantic Ocean, with notes on Nightingale Island. Bothalia 22 (1): 93 – 109.; [4] Groves, E.W. (1981). Vascular plant collections from the Tristan da Cunha group of islands. Bulletin of the British Museum (Natural History), 8 (4), 333-420).; [5] Wace, N.M. & Dickson, J.H. (1965). The terrestrial botany of the Tristan da Cunha islands. Philosophical Transactions of the Royal Society, London, B, 249:273–360.; [6]