Epilobium siskiyouense
Epilobium coloratum
Siskiyou fireweed, Siskiyou rock-fringe, Siskiyou willow-herb
eastern willow-herb, purple-leaf 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, subterete, (20–)40–85(–120) cm, freely branched distally, subglabrous proximal to inflorescence, often with raised strigillose lines decurrent from petioles, densely strigillose 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 4–10 mm;
blade narrowly lanceolate to lanceolate or narrowly elliptic, 3–10(–15) × 0.5–3 cm, subequal to internodes, base rounded to cuneate, margins sharply and irregularly serrulate, 30–75 teeth per side, veins prominent, often raised abaxially, 10–25 per side, apex acute or acuminate, surfaces subglabrous with strigillose margins and abaxial veins;
bracts abruptly reduced.
erect, compact racemes, densely canescent and glandular puberulent, or subglabrous, only ovaries pubescent.
usually upright panicles, sometimes corymbiform, rarely racemes, densely strigillose.
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 2–3 × 1.5–2.5 mm;
pedicel 5–10 mm;
floral tube 0.3–0.6 × 0.3–0.5 mm, raised ring of sparse spreading hairs at mouth inside;
sepals 1.3–3.2 × 0.5–1.5 mm, abaxial surface strigillose;
petals white, 2.5–5.5 × 2–3.8 mm, apical notch 0.5–1 mm;
filaments white, those of longer stamens 1.8–2.5 mm, those of shorter ones 1.5–2 mm;
anthers pale yellow, 0.3–0.4 × 0.2–0.4 mm;
ovary 15–30 mm, ± densely strigillose;
style erect, white, 1.5–2.8 mm, glabrous, stigma cylindrical to subcapitate, entire, 1–1.5 × 0.8–1.2 mm, surrounded by longer anthers.
25–45 mm, surfaces canescent and glandular puberulent;
pedicel 6–25 mm.
40–65 mm, surfaces strigillose;
pedicel 8–12 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 oblanceoloid, 1.2–1.7 × 0.3–0.5 mm, abruptly rounded with very short chalazal neck, brownish gray, surface evenly papillose;
coma not easily detached, cinnamon red, 8–12 mm.
= 36.
= 36.
Epilobium siskiyouense
Epilobium coloratum
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 coloratum is highly unusual in having a distribution primarily in southeastern North America. In its overall morphology, particularly leaves and flowers, it more closely resembles European species such as E. obscurum Schreber or E. tetragonum Linnaeus than any other North American species, and shares with the European species the widespread BB chromosome arrangement. There is a general resemblance between E. coloratum and the very widespread E. ciliatum (AA chromosome arrangement); hybrids between these species, known as E. ×wisconsinense Ugent, are highly sterile due to different chromosome arrangements in the parental species. The true affinities of E. coloratum are uncertain. Its occurrence on Hispaniola is also unique and possibly due to a recent introduction.
Prior to 1950, all major treatments of Epilobium attributed the name of E. coloratum to Muhlenberg (as E. coloratum Muhlenberg ex Wildenow), including C. Haussknecht (1884), W. Trelease (1891), and others. However, M. L. Fernald (1945d) noted that Index Kewensis had overlooked the 1807 publication by Biehler and virtually all treatments since that time follow the interpretation by Fernald.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
CA
OR
Flora NW
PNW Herbaria
WildflowerSearch
iNaturalist
USDA Plants Database
Go Botany
IL Wildflowers
KS Wildflowers
LA Plants
MD Biodiversity
MI Flora
MN Wildflowers
MO Plants
