Epilobium foliosum

Herbs slender. Stems strict, terete, 5–45 cm, simple to freely branched, subglabrous to strigillose proximally, strigillose and often villous and/or glandular puberulent distally. Leaves mostly alternate, often fasciculate distally, petiole 1–12 mm, blade spatulate proximally to narrowly lanceolate or linear distally, usually folded along midrib, 0.5–3 × 0.1–0.7 cm, base long-attenuate, margins subentire or scarcely serrulate, 2–4 remote teeth per side, lateral veins inconspicuous, apex blunt proximally to acute distally, surfaces subglabrous or with scattered short hairs on margins; bracts much reduced, sometimes attached to pedicel. Inflorescences suberect panicles or racemes, congested distally, with few thin branches, densely strigillose, often sparsely mixed villous and glandular puberulent. Flowers erect, often cleistogamous; buds 1.1–1.9 × 0.8–1.1 mm,often apiculate; floral tube 0.4–0.8 × 0.5–0.8 mm, with ring of short hairs at mouth inside; sepals often reddish green, 1.3–2.5 × 0.5–0.7 mm, apex subacute; petals white,1.4–2.5(–3) × 1–1.8 mm, apical notch 0.5–0.7 mm; filaments white, those of longer stamens 0.9–1.3 mm, those of shorter ones 0.5–0.7 mm; anthers 0.3–0.5 × 0.2–0.4 mm, apiculate; ovary 4–6 mm, strigillose; style white or cream, 1.2–1.7 mm, stigma subcapitate to obscurely 4-lobed, 0.3–0.4 × 0.4–0.6 mm, surrounded by longer anthers. Capsules 12–20 mm, surfaces sparsely hairy; pedicel 2–5 mm. Seeds obovoid, with slight constriction 0.2–0.3 mm from micropylar end, 0.6–0.9 × 0.3–0.5 mm, short chalazal collar 0.2–0.3 mm wide, grayish brown, surface low-papillose in ± irregular rows; coma easily detached, dingy white, 2–2.5 mm. 2n = 32.

Phenology: Flowering Apr–Aug.
Habitat: Dry, rocky slopes, roadsides, disturbed dry areas in mountains.
Elevation: 50–2300 m.

B.C., Ariz., Calif., Idaho, Oreg., Wash., Mexico (Baja California).

Discussion

Epilobium foliosum is an autogamous self-compatible species, frequently with cleistogamous flowers, and even when the flowers are somewhat larger and chasmogamous, they rarely have insect visitors. S. R. Seavey et al. (1977b) tentatively determined a specimen from Guadalupe Island, 280 km off the coast of Baja California, Mexico (Palmer 4217 in 1875) as Epilobium foliosum, and an additional sheet of the same collection (GH, as Palmer 31) had mature seeds (0.75–0.8 mm, low papillose) that verify that determination. No additional collections of this affinity since that by Palmer in 1875 have been found at this locality nor elsewhere in Mexico. Another disjunct occurrence of this species, at least 600 km east of California populations in Gila County, Arizona, is equally difficult to explain, since the collections, made between 1935 and the present, are from scattered localities in the region and do not seem obviously associated with introduction from human activity.

Selected References

None.

Lower Taxa