Description: Annual or biennial herbs; stems heteromorphic, fertile stems erect; vegetative stems prostrate, procumbent or decumbent.
Leaves simple, entire, sessile, leaves of fertile stems mostly alternate, those of vegetative stems whorled.
Inflorescences terminal, bracteate racemes. Flowers zygomorphic, pedicellate. Calyx deeply divided, with lobes equal, entire, shorter than corolla tube. Corolla with tube narrow, more or less cylindrical; limb unequally 2-lipped; lower lip much longer than upper lip; upper lip narrow, often very short, erect or reflexed. Stamens 4; staminode minute. Stigma capitate.
Capsule subglobose to obloid-ovoid, wall thin, firm, each locule dehiscing by 4 or 5 valves. Seeds more or less radically symmetrical, with 4–7 angles, surface smooth or tuberculate, ridged or not.
Distribution and occurrence: Natural to North America to northern South America, naturalised elsewhere in temperate regions.
Previously included in Linaria.
Text by Barry Conn (2014)
Taxon concept: D.A. Sutton (1988) A revision of the tribe Anthirrhineae (Oxford University Press: London & Oxford).
| | Key to the species | |
| 1 | Corolla 8–13 mm long, including 5 mm long spur, lower lip 2–6 mm long; seeds with low, entire longitudinal ridges, the intervening faces more or less smooth or with sparse, low tubercles; inflorescence with glandular hairs | Nuttallanthus canadensis |
| Corolla 14–22 mm long, including 6–11 mm long spur, with lower lip 6–11 mm long; seeds densely tuberculate, without longitudinal ridges; inflorescence glabrous | Nuttallanthus texanus |
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