7b. Viola biflora Linnaeus var. carlottae (Calder & Roy L. Taylor) B. Boivin, Naturaliste Canad. 93: 437. 1966.
Queen Charlotte twinflower violet, violette des îles de la Reine-Charlotte Queen Charlotte twinflower violet, violette des îles de la Reine-Charlotte
Viola biflora subsp. carlottae Calder & Roy L. Taylor, Canad. J. Bot. 43: 1395. 1965
Plants 5–20(–25) cm. Basal leaf blades 1.7–4.6 × 2–6.4 cm. Flowers: sepals usually with purple stripe; lowest petal 11–15 mm. Seeds 2.5 mm. 2n = 12.
Flowering Jun–Jul. Moist cliff faces, talus and rock outcrops, meadows and heathlands, rocky-grassy slopes, along streams, montane to alpine; 300–1300 m; B.C.
Variety carlottae is known from the Queen Charlotte Islands and the Brooks Peninsula of Vancouver Island, British Columbia. It is reported to hybridize with V. glabella (G. W. Douglas et al. 1998–2002, vol. 5).
One of the characteristics used by Calder and Taylor to distinguish var. carlottae was the presence of a prominent purple stripe on the sepals. V. B. Baird (1942) reported that sepals of var. biflora plants in Colorado occasionally have one purple line down the center. Purple midveins are also reported on sepals of var. biflora in Taiwan (Hsieh C. F. 1977). Some herbarium specimens at UC identified as var. carlottae from the Queen Charlotte Islands do not have a purple midvein or stripe on the sepals. The presence of a purple midvein or stripe on the sepals should not by itself be used to make a determination of var. carlottae in areas other than the Queen Charlotte Islands and Vancouver Island.
Floras that discuss the capsules of Viola biflora report that the surface is glabrous. One exception is G. W. Douglas et al. (1998–2002, vol. 5), where the capsules of var. carlottae in British Columbia are described as sparsely short-hairy.