Small-flowered tonella (Tonella tonella) COSEWIC assessment and status report: chapter 3
Species Information
Name and classification
Scientific name:
Tonella tenella (Benth.) Heller
Common name:
Small-flowered Tonella
Family:
Scrophulariaceae (Figwort family)
Major plant group:
Dicot flowering plant
Description
Small-flowered tonella, Tonella tenella (Benth.) Heller, is a member of a genus of only two species occurring in western North America (Hitchcock et al. 1959). It is the only species found in British Columbia and Canada (Pojar 2000). Tonella tenella was first recorded in Canada in 1976 (Douglas and Ruyle-Douglas 1978).
Tonella tenella is a slender, ascending to prostrate, annual herb from a delicate taproot (Figure 1; Pojar 2000). The smooth, often branched stems are 5-25 cm tall with opposite leaves. The leaves are smooth (or soft-hairy on the upper surface) and the lowermost are stalked, ovate to round, 1-2 cm long and few-toothed. The middle and upper leaves become unstalked upward and are deeply 3-lobed with the segments progressively narrowing upward. The uppermost leaves are reduced and often entire. The inflorescence consists of one to several long-stalked flowers in the axils of the bracts with smooth or minutely glandular-hairy stalks. The corollas are blue and white, short-tubular, 2-4 mm wide, and 2-lipped with the upper lip 2-lobed, the lower lip 3-lobed, and the middle lobe the largest. The calyces are up to 3 mm long, and deeply 5-lobed with the lobes longer than the tube. The 4 stamens are exserted and the fruits are ovate to globe-shaped capsules. The 2 to 4 seeds are large, 1-1.5 mm long and wingless.
Figure 1. Illustration of Tonella tenella (Line drawing from Douglas et al. 2000).
