Epilobium siskiyouense |
Epilobium rigidum |
|
|---|---|---|
|
Siskiyou fireweed, Siskiyou rock-fringe, Siskiyou willow-herb |
rigid willowherb, Siskiyou Mountains willowherb, stiff willowherb |
|
| Habit | Herbs ± suffruticose, shoots from woody caudex with barklike periderm extending to 40 cm below ground, shoots with scaly bases. | Herbs from woody caudex forming hypogeal shoots with barklike periderm. |
| Stems | 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. |
several to many, suberect or ascending, terete, 10–40 cm, simple or sparsely branched, usually glabrous and ± glaucous proximal to inflorescence, strigillose distally, sometimes densely strigillose throughout. |
| Leaves | 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. |
crowded distally, petiole 2–6 mm, blade narrowly ovate to ovate or broadly elliptic, often obovate in proximal pairs; cauline 2–4.5 × 0.8–2 cm, base rounded to attenuate, margins subentire or finely denticulate, 8–12 teeth per side, lateral veins inconspicuous, 3–5 per side, apex obtuse proximally to subacute distally, surfaces glaucous and subglabrous to densely strigillose; bracts narrower and much smaller. |
| Inflorescences | erect, compact racemes, densely canescent and glandular puberulent, or subglabrous, only ovaries pubescent. |
erect racemes, simple, ± densely strigillose, rarely mixed sparsely glandular puberulent. |
| Flowers | 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 6–11 × 4–5 mm, apiculate; pedicels 4–8 mm; floral tube 1–1.8 × 2–3 mm, with raised ring of tissue edged with spreading hairs at mouth inside; sepals often reddish green, lanceolate, 9.5–14.5 × 2.5–3.5 mm, apex acuminate, abaxial surface densely strigillose; petals pink to rose-purple, obcordate, 16–20 × 13–16 mm, apical notch 3.4–5.5 mm; filaments light pink, those of longer stamens 9–14 mm, those of shorter ones 6.5–10 mm; anthers cream, 1.8–3.5 × 1–1.9 mm; ovary 6–12 mm, densely strigillose; style cream to light pink, 14.5–18.5 mm, stigma broadly 4-lobed, 1–1.5 × 3–3.5 mm, exserted beyond anthers. |
| Capsules | 25–45 mm, surfaces canescent and glandular puberulent; pedicel 6–25 mm. |
20–35 mm, surfaces strigillose; pedicel 9–13 mm, bracts often attached 2–3 mm from base. |
| Seeds | 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, constriction 0.6–0.8 mm from micropylar end, 2.5–3.4 × 0.9–1.4 mm, chalazal collar obscure, light brown, surface papillose; coma easily detached, white, 6–8 mm. |
| 2n | = 36. |
= 36. |
Epilobium siskiyouense |
Epilobium rigidum |
|
| Phenology | Flowering Jul–Aug. | Flowering Jul–Sep. |
| Habitat | Stream banks, moist, rocky slopes, montane ridges, sometimes on serpentine areas. | Dry rocky or sandy benches, rocky hillsides, dry streambeds in coniferous forests, on seasonally moist serpentine slopes, rarely along disturbed roadsides. |
| Elevation | 1600–2500 m. [5200–8200 ft.] | 100–1200(–1500) m. [300–3900(–4900) ft.] |
| Distribution |
CA; OR
|
CA; OR
|
| Discussion | 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.) |
Within its range in northwestern California and southwestern Oregon, Epilobium rigidum is restricted to unusually dry habitats compared to most species in sect. Epilobium, but is not unlike taxa in the non-n = 18 clade, which are both perennial and annual. It is self-compatible, but with strongly protandrous flowers and an exserted stigma, and is modally outcrossing, pollinated by bees and flies. Plant vestiture varies from subglabrous to densely strigillose throughout (var. canescens), but plants with these differences can be in the same population, and no other morphological differences between them have been found. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
| Parent taxa | ||
| Sibling taxa | ||
| Synonyms | E. obcordatum subsp. siskiyouense, E. obcordatum var. laxum | E. rigidum var. canescens |
| Name authority | (Munz) Hoch & P. H. Raven: Madroño 27: 146. (1980) | Haussknecht: Oesterr. Bot. Z. 29: 51. (1879) |
| Source | FNA vol. 10. | FNA vol. 10. |
| Web links | ||