Penstemon linarioides
Penstemon linarioides var. sileri
toad-flax beardtongue, toadflax penstemon
ascending to erect, 8–50 cm, retrorsely hairy, hairs pointed or white, scalelike.
8–40 cm.
not leathery, glabrous, glabrate, or sparsely to densely retrorsely hairy, hairs pointed, sometimes appressed, white, scalelike;
cauline 6–12(–20) pairs, petiolate or sessile, 4–26 × 0.5–3.5 mm, blade oblanceolate to lanceolate or linear, base tapered to truncate, apex mucronate.
glabrous, glabrate, retrorsely hairy, or puberulent, hairs pointed, cauline 8–26 × 0.5–2 mm, blade linear.
continuous or interrupted, ± secund, 3–17 cm, axis glandular-pubescent, verticillasters 3–9(–12), cymes 1 or 2(or 3)-flowered, 1(or 2) per node;
proximal bracts lanceolate to linear, 6–25 × 0.7–1 mm;
peduncles and pedicels ascending to erect, retrorsely hairy, hairs pointed, and sparsely glandular-pubescent.
calyx lobes ovate, rarely lanceolate, 4–7(–9) × 2–3 mm, broadly scarious-margined, apex acute to acuminate, glandular-pubescent, hairs pointed;
corolla blue or lavender, lined internally abaxially with reddish purple nectar guides, ventricose-ampliate, 16–20 mm, moderately white- or yellowish villous internally abaxially, tube 5–6 mm, throat abruptly inflated, 5.5–8 mm diam., slightly 2-ridged abaxially;
stamens: longer pair reaching orifice or slightly exserted, filaments glabrous, pollen sacs opposite, navicular, 0.9–1.3 mm, sutures papillate;
staminode 6–8 mm, exserted, flattened distally, 0.3–0.5 mm diam., tip straight to recurved, distal 1–5 mm densely pilose, hairs yellow or golden yellow, to 1.2 mm, rest of distal 1–7 mm glabrous or sparsely to moderately pilose;
style 10–11 mm.
staminode: distal 3–5 mm densely pilose, hairs yellow, to 1.2 mm, rest of distal 2–3 mm sparsely to moderately pilose.
5–9 × 3.5–5 mm.
Penstemon linarioides
Penstemon linarioides var. sileri
Varieties 4 (4 in the flora).
Penstemon linarioides is widespread and highly variable. D. D. Keck (1937) recognized seven subspecies on the basis of habit, pubescence, leaf shape, and staminode bearding. Some of the variation on which those subspecies are based appears to be clinal or too variable within or among regional populations to be of taxonomic value.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Variety sileri is known from northern Arizona, southern Nevada, and southwestern Utah. Plants with glabrous or nearly glabrous leaves from northern Arizona and southern Utah have been referred to var. viridis. As noted by N. H. Holmgren (1984), such forms occur sporadically through much of the range of var. sileri, suggesting that taxonomic recognition of var. viridis is unwarranted. Some specimens included in var. sileri from northern Arizona, especially from the Kaibab Plateau, have the habit of subsp. compactifolius (included here in var. linarioides) but the leaf pubescence of var. sileri (or var. viridis). Holmgren identified three morpho-geographic races that may warrant recognition.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
1. Leaves glabrous, glabrate, retrorsely hairy, or pubescent, hairs pointed. | var. sileri |
1. Leaves sparsely to densely retrorsely hairy, hairs appressed, white, scalelike. | → 2 |
2. Cauline leaf blades oblanceolate, distals sometimes lanceolate, 1.5–3.5 mm wide. | var. maguirei |
2. Cauline leaf blades oblanceolate to linear, 0.5–2 mm wide. | → 3 |
3. Staminodes: distal 3–5 mm densely pilose, hairs golden yellow or yellow, to 1 mm, rest of distal 1–4 mm sparsely to moderately pilose. | var. linarioides |
3. Staminodes: distal 1 mm densely pilose, hairs yellow, to 0.8 mm, rest of distal 3–4 mm glabrous or sparsely pilose (with much shorter hairs). | var. coloradoensis |
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