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Linear-leaved Willowherb - Epilobium palustre var. gracile
Other Names:  Epilobium leptophyllum

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Native Species

Global Rank: G5
State Rank: SNR
C-value:


Agency Status
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General Description
See species description.

Phenology
Erect perennial herbs, often robust and rank, spreading by threadlike, nearly leafless epigeous stolons that terminate in compact fleshy turions. Stems erect, terete, 15-95 cm tall, simple to well branched in larger plants, covered throughout with dense incurved strigillose hairs, sometimes mixed with glandular ones on the inflorescence, lacking decurrent lines from the leaf bases. Leaves linear to very narrowly elliptic, 2-7.5 cm long, 0.15-0.7 cm wide, not much reduced in size on inflorescence, usually longer than internodes, densely strigillose-pubescent both sides, increasing up stem, sometimes revolute, subacute especially in upper pairs, subentire with inconspicuous lateral veins, subsessile, occasinally fascicled. Inflorescence erect, crowded, leafy. Flowers erect; floral tube 0.8-1.5 mm long, 1.2-1.8 mm wide, densely strigillose outside, with a ring of spreading hairs inside at the mouth; sepals 2.5-4.5 mm long, 0.9-1.3 mm wide, green, strigillose; petals 3.5-7 mm long, 1.6-4 mm wide, white to light pink, obcordate with apical notch 1-1.8 mm deep; anthers 0.6-0.9 mm wide, cream, filaments white or cream, unequal, 0.8-3.5 mm long, at least the longer stamens usually shedding pollen directly onto stigma; ovaries 12-18 mm long, densely white canescent, rarely with an admixture of gland-tipped hairs, on pedicels 5-12 mm long, style 2-3.8 mm long, deep cream, stigma cream, narrowly clavate, rarely exserted beyond stamens. Capsules 3.5-8 cm long, slender, canescent, on pedicels 1.5-3.5 cm long; seeds 1.5-2.2 mm long, 0.5-0.7 mm wide, attenuate, narrowly obovoid, densely papillose, chalazal collar sometimes quite pronounced, 0.2 mm or less long, coma (tuft of hairs) 6-8 mm long, dingy white, persistent (Hoch 1986, in Flora of the Great Plains).

Hoch's description is based on recognition of this taxon as a species, not subspecies.

Range Comments
Widespread across much of North America excluding the southeast (Kartesz 2009).

Observations in Montana Natural Heritage Program Database
Number of Observations: 2

(Click on the following maps and charts to see full sized version) Map Help and Descriptions
Relative Density

Recency

 

(Observations spanning multiple months or years are excluded from time charts)



Habitat
Marshes, seepage areas, and mesic disturbed sites (Hoch 1986).

Ecology
POLLINATORS
The following animal species have been reported as pollinators of this plant species or its genus where their geographic ranges overlap: Bombus bifarius, Bombus centralis, Bombus fervidus, Bombus flavifrons, Bombus frigidus, Bombus melanopygus, Bombus mixtus, Bombus rufocinctus, Bombus sylvicola, Bombus ternarius, Bombus sitkensis, Bombus occidentalis, Bombus griseocollis, Bombus impatiens, Bombus insularis, Bombus suckleyi, and Bombus kirbiellus (Thorp et al. 1983, Mayer et al. 2000, Colla and Dumesh 2010, Wilson et al. 2010, Colla et al. 2011, Koch and Strange 2012, Koch et al. 2012, Pyke et al. 2012, Williams et al. 2014).


References
  •  Literature Cited Above
  •  Additional References
  •  Web Search Engines for Articles on "Linear-leaved Willowherb"
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Citation for data on this website:
Linear-leaved Willowherb — Epilobium palustre var. gracile.  Montana Field Guide.  .  Retrieved on , from