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blue toadflax, Canada toadflax, linaire du Canada, old field toadflax

Fertile stems

1–4(–7), simple, rarely distally branched, 11–70 cm.


blades of sterile-stem leaves narrowly elliptic to obovate, 2–12 × 0.5–3 mm, blades of fertile-stem leaves linear, 5–43 × 0.5–2.2 mm.


1–18 cm;

bracts narrowly oblanceolate or lanceolate to narrowly elliptic, 1.1–3 mm.


erect, 1.8–5.5 mm in fruit, sparsely glandular-pubescent, sometimes glabrous, hairs to 0.1 mm.


calyx lobes linear-lanceolate to narrowly ovate, 2.1–3.5 × 0.4–1 mm, proximally sparsely glandular-pubescent, sometimes glabrous;

corolla white to blue, 8–14 mm, spurs straight or curved, 2–7 mm, abaxial lip 2–4.5 mm, adaxial 1.2–2(–3) mm.


oblong-ovoid, 2.6–3.9 × 2.6–3.3 mm.


black or gray, 0.3–0.5 mm, edges sharp, faces obscurely tuberculate.


= 12.

Nuttallanthus canadensis

Phenology Flowering Feb–Jul(–Sep).
Habitat Sandy prairies, woodlands, roadsides, fallow fields, disturbed sites.
Elevation 0–300 m. (0–1000 ft.)
from FNA
AL; AR; CA; CT; DC; DE; FL; GA; IA; IL; IN; KS; LA; MA; MD; ME; MI; MN; MO; MS; MT; NC; ND; NE; NH; NJ; NY; OH; OK; PA; RI; SC; SD; TN; TX; VA; VT; WA; WI; WV; BC; NB; NS; ON; PE; QC [Introduced in e Europe (Russia)]
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Nuttallanthus canadensis and N. texanus are sympatric through much of their ranges. In Texas, where they sometimes occur in mixed populations, R. Kral (1955) observed that N. canadensis bloomed and set fruit earlier than did N. texanus.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 17, p. 41.
Parent taxa Plantaginaceae > Nuttallanthus
Sibling taxa
N. floridanus, N. texanus
Synonyms Antirrhinum canadense, Linaria canadensis
Name authority (Linnaeus) D. A. Sutton: Revis. Antirrhineae, 457. (1988)
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