Epilobium siskiyouense
Epilobium montanum
Siskiyou fireweed, Siskiyou rock-fringe, Siskiyou willow-herb
broad-leaf willow-herb, tooth willow-herb, willowherb
several to many, erect to ascending, loosely clumped, terete, 10–25 cm, rarely branched distal to base, usually short-villous and strigillose throughout, mixed sparsely glandular puberulent distally, rarely subglabrous proximal to inflorescence.
erect, terete, (5–)20–95 cm, often well branched, especially distally, densely strigillose proximal to inflorescence, without decurrent lines, mixed strigillose and glandular puberulent distally.
opposite proximal to inflorescence, alternate and usually crowded distally, sessile;
blade gray-green, narrowly to broadly ovate, 1.3–2.6 × 0.8–2 cm, base rounded to subcordate, margins usually serrulate, 6–12 teeth per side, rarely subentire, veins inconspicuous, 3–5 per side, apex rounded proximally to acute distally, surfaces sparsely short-villous to subglabrous and glaucous;
bracts much reduced.
opposite proximal to inflorescence, alternate distally, petiole 1–6 mm;
blade dark green, narrowly ovate to ovate, 3–8 × 1.5–3.4 cm, subequal to internodes, base broadly cuneate to truncate, margins irregularly serrulate with 20–30 teeth per side, veins prominent, 3–5 per side, apex acuminate to acute, surfaces strigillose, especially along veins and margins;
bracts much reduced.
erect, compact racemes, densely canescent and glandular puberulent, or subglabrous, only ovaries pubescent.
nodding to erect, racemes or loose panicles, strigillose and glandular puberulent.
erect;
buds often purplish green, 9–11 × 3.5–5 mm, blunt;
pedicel 6–12 mm;
floral tube 2.1–4 × 2.9–5 mm, prominent ring of tissue 0.3–0.6 mm wide, edged by spreading hairs, 0.9–1.8 mm from base of tube inside;
sepals purplish green, 5–10.5 × 2–3.5 mm, apex acute;
petals pink to rose-purple, obcordate, 10–22.5 × 9.5–15.5 mm, apical notch 2–6.5 mm;
filaments cream, those of longer stamens 6.5–14 mm, those of shorter ones 3.5–11 mm;
anthers cream 1.9–3.3 × 0.7–1.2 mm;
ovary 12–22 mm, ± densely canescent and glandular puberulent;
style white to light pink, 10.5–18 mm, sparsely villous just proximal to stigma, stigma broadly 4-lobed, 1–1.8 × 2.4–4.2 mm, exserted beyond anthers.
erect;
buds 4–5x 1.5–3 mm;
pedicel 2–18 mm;
floral tube 1.2–2 × 1.5–2.5 mm, conspicuous ring of spreading hairs at mouth inside;
sepals often flushed red, keeled, 5–6.5 × 1.2–1.7 mm, abaxial surface strigillose and glandular puberulent;
petals rose-purple, obcordate, 7.5–10 × 4–5.5 mm, apical notch 2.7–4.2 mm;
filaments light pink, those of longer stamens 3.5–5.5 mm, those of shorter ones 1.5–2.4 mm;
anthers yellow, 1–1.2 × 0.5–0.6 mm;
ovary 20–30 mm, strigillose and glandular puberulent;
style rose-purple to white, 3.5–7.5 mm, glabrous or with scattered long hairs near base, stigma deeply 4-lobed, 1.5–2 × 2.5–4 mm, lobes 1.2–1.8 mm, exserted beyond or, sometimes, surrounded by anthers.
25–45 mm, surfaces canescent and glandular puberulent;
pedicel 6–25 mm.
40–80 mm, surfaces strigillose and glandular puberulent;
pedicel 8–20 mm.
narrowly obovoid, 1.4–1.9 × 0.6–0.7 mm, with low, obscure chalazal collar, light brown, surface papillose;
coma easily detached, somewhat tawny, 4–8 mm.
obovoid, 1–1.2 × 0.4–0.5 mm, chalazal collar inconspicuous, 0.6–0.8 mm wide, brown, surface coarsely papillose;
coma readily detached, dull white, 5–6 mm.
= 36.
= 36.
Epilobium siskiyouense
Epilobium montanum
Epilobium siskiyouense is endemic to the Klamath region in southwestern Oregon (Jackson County) and north-central California in the Salmon, Scott Bar, and Siskiyou mountains of Siskiyou and Trinity counties. As noted by Hoch and Raven, this geographical range and several morphological features appear to be intermediate between those of E. obcordatum and E. rigidum. All three species have unusually large flowers (12–26 mm) with four-lobed stigmas, and as a group are quite distinct from their congeners in the region. Despite these similarities, the three taxa differ substantially in details of floral structure, especially regarding the dimensions of the floral tube. Specifically, E. rigidum has mean petal length 18.2 mm, floral tubes 1–1.6 × 2.5–3.6 mm; E. siskiyouense mean petal length 17.1 mm, floral tubes 2.1–4 × 2.9–5 mm; and E. obcordatum mean petal length 18.6 mm, floral tubes 3.2–5.2 × 2.2–3.6 mm. Thus, in flowers that are similar in overall size and aspect, E. rigidum has a very short, broad floral tube, E. obcordatum has a relatively long, narrow tube, and E. siskiyouense has a tube intermediate in size and shape. In terms of the ratio of tube length to width, the three taxa do not overlap. Although these characters are difficult to include in a key (since they require floral dissection and/or precise measurements), they are diagnostic for these species.
Epilobium siskiyouense has an additional diagnostic floral character that is unique in the genus. Whereas most other species of Epilobium have a simple ring of spreading hairs, sometimes with a low ridge of tissue near the mouth of the floral tube, E. siskiyouense has a relatively broad ring of tissue (0.3–0.6 mm wide), shaped like a washer, from which spreading hairs arise; this feature may provide protection for the nectar.
Epilobium siskiyouense has two distinct patterns of vestiture on the stems. In some specimens, the lower stems are mixed canescent and glandular puberulent and the inflorescence only glandular puberulent. In other specimens, the stems are subglabrous below a sparsely canescent and glandular puberulent inflorescence. There is no obvious correlation of this difference with any other morphological, ecological, or geographical factors.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Epilobium montanum is native and widely distributed throughout Europe and in Asia at least as far east as the Ural Mountains and the Caucasus, and in Japan (A. W. Lievens and P. C. Hoch 1999). It also is questionably naturalized on Campbell Island, New Zealand (P. H. Raven and T. E. Raven 1976). Although E. montanum was first collected in 1894 in the vicinity of St. John’s, Newfoundland, and clearly naturalized in that area, it does not appear to have spread appreciably in eastern North America, unlike European adventives such as E. hirsutum or E. parviflorum. The collection by F. C. Seymour in 1971 in Maine may be an independent introduction. Collections of E. montanum in the University of British Columbia Botanical Garden in Vancouver appeared to have been ephemeral, but more recent collections in ruderal areas in that region suggest that it has naturalized there. Like other European introductions, E. montanum has the BB chromosome arrangement (S. R. Seavey and P. H. Raven 1977).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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