The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

glaucous willowherb, glaucus willowherb, smooth willowherb

Photo is of parent taxon

glaucus willowherb, smooth willowherb

Habit Herbs with branching, wiry basal shoots with crowded, often dark, scales.
Stems

many, erect or ascending, often densely clumped, slender, terete, 5–75(–85) cm, simple or distally branched, glabrous and glaucous, sometimes strigillose and/or mixed glandular puberulent distally, rarely with faint raised strigillose lines decurrent from margins of distal petioles.

5–35 cm, sometimes sparsely strigillose and glandular puberulent distally, rarely with faint raised strigillose lines decurrent from margins of distal petioles.

Leaves

opposite and crowded proximal to inflorescence, alternate and widely spaced distally, subsessile and ± clasping;

blade light green or blue-green, very narrowly lanceolate to narrowly ovate or elliptic, (0.5–)1–7.2 × (0.3–)0.5–1.8 cm, base cuneate, margins subentire or faintly denticulate, 8–15 teeth per side, veins inconspicuous, 3–6 per side, apex obtuse proximally to acute distally, glabrous and glaucous;

bracts much reduced and narrower.

blades usually blue-green, lanceolate to narrowly ovate or elliptic, (0.5–)1–3.4 × (0.3–)0.7–1.8 cm, length/width ratio less than 4.

Inflorescences

erect racemes, glabrous or ± sparsely glandular puberulent, sometimes mixed strigillose.

Flowers

erect;

buds 2.5–5 × 2–3.5 mm;

pedicel 2–11(–20) mm;

floral tube 0.7–2.3 × 1–2.5 mm, ring of spreading hairs at mouth inside or without a ring;

sepals often red-tipped, sometimes keeled, 2.5–7.5 × 0.8–2 mm, abaxial surface glabrous or strigillose and/or glandular puberulent;

petals usually light pink to rose-purple, rarely white, 3.4–10(–12) × 1.8–5 mm, apical notch 0.5–3 mm;

filaments purple to white or cream, those of longer stamens 2.4–5(–6) mm, those of shorter ones 1.4–4 mm;

anthers light yellow, 0.5–1.2(–1.5) × 0.3–0.7 mm;

ovary 10–42 mm, subglabrous to sparsely mixed strigillose and glandular puberulent;

style light yellow or cream, 1.7–5(–7) mm, stigma clavate to subcapitate, 0.8–3 × 0.5–1.2 mm, usually surrounded by, rarely exserted beyond, longer anthers.

floral tube 0.9–1.4 × 1–2.2 mm;

sepals 2.5–5.2 × 0.8–1.6 mm;

petals rose-purple to pink, 3.4–8 × 1.8–3.9 mm;

filaments of longer stamens 2.4–5 mm, those of shorter ones 1.6–3 mm;

ovary 10–34 mm, style 2.2–3.6 mm.

Capsules

15–75 mm, with small protuberance at base, surfaces subglabrous to sparsely mixed strigillose and glandular puberulent;

pedicel 5–18(–25) mm.

15–45(–55) mm.

Seeds

narrowly obovoid, 0.7–1(–1.3) × 0.3–0.5 mm, chalazal collar inconspicuous, light brown or gray, surface coarsely papillose in longitudinal rows;

coma readily detached, white, 4–9 mm.

2n

= 36.

Epilobium glaberrimum

Epilobium glaberrimum subsp. fastigiatum

Phenology Flowering Jun–Sep.
Habitat Rocky, well drained soil, moist alpine slopes, seepage, talus slope, stream banks, bogs, mainly upper montane to alpine.
Elevation (1000–)1200–3500 m. ((3300–)3900–11500 ft.)
Distribution
from USDA
w North America; nw Mexico
[WildflowerSearch map]
[BONAP county map]
from FNA
CA; ID; MT; NV; OR; UT; WA; WY; AB; BC
[BONAP county map]
Discussion

Subspecies 2 (2 in the flora).

Epilobium glaberrimum is restricted mainly to the Sierra Nevada-Cascade region, but also (subsp. fastigiatum) in the northern Rocky Mountains. It is one of the more easily identified species due to its consistently glabrous and glaucous aspect. Although the distributions and elevational ranges of the two subspecies appear to overlap extensively, they are largely allopatric with subsp. glaberrimum occurring in lower to mid montane zones and subsp. fastigiatum in upper montane to subalpine zones in the southern part of its range, and in lower zones farther north.

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

Subspecies fastigiatum occurs primarily along the Sierra Nevada-Cascade axis, but also ranges through the Basin Ranges to the Rocky Mountains from northern Wyoming to southern Alberta and British Columbia.

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

Key
1. Stems 20–75(–85) cm; leaf blades (2–)3–7.2 cm, very narrowly lanceolate to lanceolate or narrowly elliptic (length/width ratio more than 4); capsules 45–75 mm; petals (4–)5–10(–12) mm.
subsp. glaberrimum
1. Stems 5–35 cm; leaf blades (0.5–)1–3.4 cm, lanceolate to narrowly ovate or elliptic (length/width ratio less than 4); capsules 15–45(–55) mm; petals 3.4–8 mm.
subsp. fastigiatum
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 > Epilobium glaberrimum
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. 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. smithii, E. suffruticosum, E. torreyi
E. glaberrimum subsp. glaberrimum
Subordinate taxa
E. glaberrimum subsp. fastigiatum, E. glaberrimum subsp. glaberrimum
Synonyms E. fastigiatum var. glaberrimum E. affine var. fastigiatum, E. concinnum, E. fastigiatum, E. glaberrimum var. fastigiatum, E. glaberrimum var. latifolium, E. platyphyllum
Name authority Barbey in W. H. Brewer et al.: Bot. California 1: 220. (1876) (Nuttall) Hoch & P. H. Raven: Ann. Missouri Bot. Gard. 71: 342. (1984)
Web links