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glandular willowherb, Rocky Mountain willowherb, Rocky Mountain willowweed, épilobe des rocheuses

Smith's willowherb

Habit Herbs usually with sessile, fleshy, underground turions, or sometimes thick, elongated shoots with dark, decussate scales. Herbs with sprawling, wiry underground soboles with brownish tan scalelike leaves, arising from semi-woody extended caudex.
Stems

erect, strict, terete, 4–55 cm, simple or well branched in age, subglabrous proximally to mixed strigillose and glandular puberulent distally, with raised strigillose lines decurrent from margins of petioles.

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 and reduced distally, often ± appressed, usually subsessile, rarely petiole 1–3 mm, often clasping;

blade obovate proximally to ovate, lanceolate, or narrowly elliptic distally, 1–5.5(–6.5) × 0.4–2(–2.4) cm, base rounded or obtuse, margins low denticulate, 9–30 teeth per side, veins ± conspicuous, 3–6 per side, apex subacute, surfaces subglabrous with strigillose margins;

bracts much reduced.

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, sometimes nodding in bud, racemes, sometimes sparsely branched.

erect or sometimes nodding in bud, short racemes, glandular puberulent.

Flowers

erect;

buds 2–3.5 × 1.8–2.5 mm;

pedicel 0–1 mm;

floral tube 0.8–1.4 × 0.8–1.9 mm, ring of sparse spreading hairs at mouth inside;

sepals sometimes flushed red, 1.2–3.5 × 0.6–1.4 mm, abaxial surface strigillose and sometimes mixed glandular puberulent;

petals usually white, infrequently pink, 2.2–5(–7) × 1.7–3.2 mm, apical notch 0.4–1.5 mm;

filaments usually cream, rarely light pink, those of longer stamens 2–3.5 mm, those of shorter ones 1–2 mm;

anthers cream to light yellow, 0.3–0.8 × 0.3–0.5 mm;

ovary 9–30 mm, densely strigillose and glandular puberulent;

style cream or yellow, 1.6–2.8 mm, stigma usually narrowly to broadly clavate, rarely subcapitate, 1–3 × 0.8–2 mm, surrounded by at least longer anthers.

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

30–55(–70) mm, surfaces mixed strigillose and glandular puberulent; usually subsessile, rarely pedicel 1–5 mm, often appressed to stem.

24–65 mm, surfaces glandular puberulent;

pedicel 10–30 mm.

Seeds

very narrowly obovoid, 1–1.6(–1.8) × 0.4–0.6 mm, chalazal collar 0.1–0.2 mm, light brown or gray, surface rugose to papillose;

coma usually readily detached, white, 3–9 mm.

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.

= 36.

Epilobium saximontanum

Epilobium smithii

Phenology Flowering Jul–Sep. Flowering Jul–Sep.
Habitat Montane semi-shaded stream banks, damp meadows, mossy seeps, wet slatey cliffs, disturbed or seasonally damp areas. Moist talus or scree slopes, crevices of rocky outcrops, often on south-facing subalpine to alpine slopes.
Elevation 0–3700 m. (0–12100 ft.) (1000–)1500–3000 m. ((3300–)4900–9800 ft.)
Distribution
from FNA
AZ; CA; CO; ID; MT; NM; NV; OR; SD; UT; WY; AB; BC; MB; NF; ON; QC
[WildflowerSearch map]
[BONAP county map]
from FNA
MT; UT; WA; AB; BC
[BONAP county map]
Discussion

Epilobium saximontanum is morphologically similar to E. ciliatum (especially subsp. glandulosum) with which it also shares the AA chromosome arrangement. However, in addition to its fleshy compact turions, it very characteristically has notably appressed capsules, unlike most other species in the genus, and a notably strict habit.

The distribution of Epilobium saximontanum is unusual; it includes the Rocky Mountain region, only barely reaching the high southern Sierra Nevada, disjunct to the Black Hills of South Dakota, and more widely in eastern Canada, from the shores of Hudson Bay to Newfoundland. Specimens are fairly uniform across this wide and rather discontinuous range, although locally they show some variability, possibly due to hybridization with any of several species that may be sympatric with it. H. Lewis and D. M. Moore (1962) reported hybrids between E. saximontanum (cited as E. brevistylum) and E. ciliatum subsp. ciliatum (cited as E. adenocaulon) from Colorado, and herbarium specimens with E. saximontanum and apparent hybrids are not uncommon.

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

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.

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

Source FNA vol. 10. FNA vol. 10.
Parent taxa Onagraceae > subfam. Onagroideae > tribe Epilobieae > Epilobium > sect. Epilobium Onagraceae > subfam. Onagroideae > tribe Epilobieae > Epilobium > sect. Epilobium
Sibling taxa
E. anagallidifolium, E. arcticum, E. brachycarpum, E. campestre, E. canum, E. ciliatum, E. clavatum, E. cleistogamum, E. coloratum, E. davuricum, E. densiflorum, E. densum, E. foliosum, E. glaberrimum, E. hallianum, E. hirsutum, E. hornemannii, E. howellii, E. lactiflorum, E. leptocarpum, E. leptophyllum, E. luteum, E. minutum, E. mirabile, E. montanum, E. nevadense, E. nivium, E. obcordatum, E. obscurum, E. oreganum, E. oregonense, E. pallidum, E. palustre, E. parviflorum, E. rigidum, E. septentrionale, E. siskiyouense, E. smithii, E. suffruticosum, E. torreyi
E. anagallidifolium, E. arcticum, E. brachycarpum, E. campestre, E. canum, E. ciliatum, E. clavatum, E. cleistogamum, E. coloratum, E. davuricum, E. densiflorum, E. densum, E. foliosum, E. glaberrimum, E. hallianum, E. hirsutum, E. hornemannii, E. howellii, E. lactiflorum, E. leptocarpum, E. leptophyllum, E. luteum, E. minutum, E. mirabile, E. montanum, E. nevadense, E. nivium, E. obcordatum, E. obscurum, E. oreganum, E. oregonense, E. pallidum, E. palustre, E. parviflorum, E. rigidum, E. saximontanum, E. septentrionale, E. siskiyouense, E. suffruticosum, E. torreyi
Synonyms E. adenocaulon subsp. rubescens, E. drummondii, E. drummondii var. latiusculum, E. latiusculum, E. ovatifolium, E. rubescens, E. scalare, E. stramineum E. clavatum var. glareosum, E. glareosum
Name authority Haussknecht: Oesterr. Bot. Z. 29: 119. (1879) H. Léveillé: Repert. Spec. Nov. Regni Veg. 5: 8. (1908)
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