Nuttallanthus canadensis
Nuttallanthus
blue toadflax, Canada toadflax, linaire du Canada, old field toadflax
blue toadflax, toadflax
1–4(–7), simple, rarely distally branched, 11–70 cm.
heteromorphic, sterile prostrate or decumbent to ascending, glabrous, fertile erect, glabrous or glandular-pubescent distally.
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.
cauline, whorled on sterile stems, alternate, sometimes whorled proximally, on fertile stems;
petiole absent or essentially so;
blade not fleshy, not leathery, margins entire.
1–18 cm;
bracts narrowly oblanceolate or lanceolate to narrowly elliptic, 1.1–3 mm.
terminal, spikelike racemes;
bracts present.
erect, 1.8–5.5 mm in fruit, sparsely glandular-pubescent, sometimes glabrous, hairs to 0.1 mm.
present;
bracteoles absent.
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.
bisexual;
sepals 5, proximally connate, calyx ± symmetric, short-cupulate, lobes linear-lanceolate or lanceolate to narrowly ovate or oblong;
corolla white to blue or pale violet, bilaterally symmetric, bilabiate and personate, tubular, tube base not gibbous, spurred abaxially, lobes 5, abaxial 3, adaxial 2, abaxial lip much longer than adaxial and strongly arched at palate;
stamens 4, proximally adnate to corolla, didynamous, filaments glabrous;
staminode 0 or 1, minute;
ovary 2-locular, placentation axile;
stigma capitate.
capsules, 2–4.8 mm, dehiscence poricidal by 4 or 5 irregular valves in each locule.
oblong-ovoid, 2.6–3.9 × 2.6–3.3 mm.
black or gray, 0.3–0.5 mm, edges sharp, faces obscurely tuberculate.
100–200, black or gray, angled, wings absent.
= 6.
= 12.
Nuttallanthus canadensis
Nuttallanthus
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.)
Species 4 (3 in the flora).
Species of Nuttallanthus native to the New World have been included historically in Linaria; F. W. Pennell (1919, 1935) included them in the invalidly published sect. Lectoplectron Pennell. Sutton erected Nuttallanthus to accommodate these species based on their corollas with larger abaxial lips relative to adaxial lips, weakly developed palates, and less well-developed spurs, and their angled, four- to seven-ridged seeds. M. Fernández-Mazeucos et al. (2013) presented molecular evidence for the monophyly of Nuttallanthus as a member of one of three basal clades within Linaria. Support for two of the three basal clades, including one containing Nuttallanthus, was sufficiently low that the authors concluded that further studies were needed to determine whether Nuttallanthus should be included in Linaria as a section. Consequently, Nuttallanthus is maintained here as a distinct genus. Nuttallanthus subandinus D. A. Sutton occurs in South America.
Nuttallanthus species usually grow in well-drained, sandy soil in native plant communities that experience disturbances and also in disturbed habitats, including former cropland. The species sometimes grow in mixed populations; the North American species are cross incompatible (P. T. Crawford and W. J. Elisens 2006).
In the descriptions, corolla length is the distance from the distal point of the medial lobe of the abaxial lip to the distal point of the spur. In addition to chasmogamous flowers, cleistogamous flowers are produced early and late in the reproductive cycle. Fruits produced by cleistogamous flowers are smaller and contain fewer seeds than do fruits produced by chasmogamous flowers (P. T. Crawford and W. J. Elisens 2006).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Corolla spurs 0.1–0.5 mm; pedicels 6–14 mm in fruit, ascending, sometimes erect, hairs to 0.3 mm. | N. floridanus |
1. Corolla spurs 2–11 mm; pedicels 1.8–8(–9) mm in fruit, erect, hairs to 0.1 mm. | → 2 |
2. Edges of seeds sharp, faces obscurely tuberculate; corollas 8–14 mm, spurs 2–7 mm. | N. canadensis |
2. Edges of seeds rounded, rarely angled or irregularly dentate, faces prominently pointed-tuberculate, rarely with rounded ridges and scattered, rounded tubercles; corollas (11–)14–22 mm, spurs 4.5–11 mm. | N. texanus |
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BC, 
OR, 
WA - Local Web sites:
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PNW Herbaria, Turner Photog. 
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