Epilobium siskiyouense
Epilobium smithii
Siskiyou fireweed, Siskiyou rock-fringe, Siskiyou willow-herb
Smith's 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.
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.
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 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.
erect, compact racemes, densely canescent and glandular puberulent, or subglabrous, only ovaries pubescent.
erect or sometimes nodding in bud, short racemes, 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.
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.
25–45 mm, surfaces canescent and glandular puberulent;
pedicel 6–25 mm.
24–65 mm, surfaces glandular puberulent;
pedicel 10–30 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.
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.
= 36.
= 36.
Epilobium siskiyouense
Epilobium smithii
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 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.)
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