Epilobium smithii

Herbs with sprawling, wiry under­ground soboles with brownish tan scalelike leaves, arising from semi-woody ex­tended caudex. Stems 10–30+, ascending to erect, clumped, terete, 6–35 cm, usually simple, rarely slightly branched distally, strigillose throughout, especially on raised lines decurrent from margins of petioles, densely glandular puberulent distally. Leaves opposite proximal to inflorescence, alternate distally, petiole 0–5 mm; blade dark or grayish green, lanceolate to subovate, 1–3.8 × 0.3–1.5 cm, base attenuate proximally to rounded distally, margins low-denticulate with 4–15 teeth per side, lateral veins usually indistinct, 2–5 per side, apex subacute to blunt, surfaces sparsely glandular puberulent on margins and veins; bracts scarcely reduced. Inflorescences erect or sometimes nodding in bud, short racemes, glandular puberulent. Flowers few, erect or sometimes slightly nodding in bud; buds 3–4.5 × 2.5–3 mm; pedicel 5–10 mm; floral tube 1–2.2 × 1.2–2.2 mm, with raised ring of sparse hairs at mouth inside; sepals often red along margins, lanceolate, 3–4.8 × 1–2.1 mm, abaxial surface scattered mixed glandular puberulent and strigillose; petals dark pink to rose-purple, obcordate, (3–)5–7 × (2–)3–4.5 mm, apical notch 1–2.5 mm; filaments pale pink, those of longer stamens 2.4–4.2 mm, those of shorter ones 1.2–2.6 mm; anthers pale yellow, 0.5–1.1 × 0.3–0.7 mm; ovary 15–22(–26) mm, densely glandular puberulent; style cream, 2.5–3.5 mm, often with scat­tered hairs near base, stigma clavate to subcapitate, 0.8–1.5 × 0.5–1 mm, surrounded by longer anthers. Capsules 24–65 mm, surfaces glandular puberulent; pedicel 10–30 mm. Seeds narrowly obovoid, (1.2–)1.4–1.7 × 0.4–0.7 mm, chalazal collar conspicuous, 0.08–0.15 ×0.15–0.25 mm, light brown, surface densely irregular papillose; coma persistent, dull white, 6–12 mm. 2n = 36.

Phenology: Flowering Jul–Sep.
Habitat: Moist talus or scree slopes, crevices of rocky outcrops, often on south-facing subalpine to alpine slopes.
Elevation: (1000–)1500–3000 m.

Distribution

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Alta., B.C., Mont., Utah, Wash.

Discussion

Epilobium smithii has a restricted distribution, relatively abundant on the Olympic Peninsula (Washington) and Vancouver Island (British Columbia) and more scattered across northern Washington to the Waterton-Glacier International Peace Park in Montana and adjacent Alberta. A single collection from the Uinta Mountains in Utah suggests that the range may be larger.

Although Epilobium smithii has been generally ignored, it differs strikingly from most other species of Epilobium by virtue of being densely glandular puberulent all around the upper stems. It is most similar to E. clavatum, with which some authors combined it and with which it may be closely related in the CC chromosome group.

Collections of Epilobium smithii are often mixed and include other species such as E. anagallifolium, E. clavatum, and E. lactiflorum, and less often E. leptocarpum and E. mirabile, the range of which all overlap with that of E. smithii. Despite the observed sympatry of these species, their similarity in floral features, and their capacity to hybridize (S. R. Seavey and P. H. Raven 1978), few obvious hybrids have been found.

Selected References

None.

Lower Taxa

None.