Eremothera boothii

(Douglas) W. L. Wagner & Hoch

Syst. Bot. Monogr. 83: 209. 2007.

Basionym: Oenothera boothii Douglas in W. J. Hooker Fl. Bor.-Amer. 1: 213. 1832
Synonyms: Camissonia boothii (Douglas) P. H. Raven Sphaerostigma boothii (Douglas) Walpers
Treatment appears in FNA Volume 10.

Herbs slender or stout, glabrate to strigillose or villous, and/or glandular puberulent, especially in inflorescence. Stems usually well branched at base and distally, 3–65 cm, usually flowering only distally. Leaves cauline, sometimes with lower ones clustered near base, these often withered by flowering, 1–11(–13) × 0.2–2.2(–3) cm; petiole 0–6 cm; blade very narrowly elliptic to narrowly ovate, lanceolate, or oblanceolate, margins denticulate, serrulate, sinuate-toothed, or subentire. Inflorescences nodding. Flowers opening at sunset; floral tube (2–)3–8 mm, villous in proximal 1/2 inside; sepals (2.7–)4–8 mm; petals usually white fading pink, rarely red and fading red, (3–)3.5–9 mm; episepalous filaments (1.5–)2–5.8 mm, epipetalous filaments slightly shorter, anthers (1–)1.8–2.3 mm; style (6.5–)8.2–13.5(–15) mm, villous near base, stigma 1.2–2 mm diam., exserted beyond anthers at anthesis. Capsules cylindrical and thickened proximally, spreading to curved downward, contorted to straight, terete or 4-angled, 8–35 × 0.9–3.8 mm, held on dried plants and regularly but tardily dehiscent. Seeds usually dimorphic, rarely monomorphic, those with relatively smooth surfaces light brown, 1.4–2.1 × 0.5–0.7 mm, those of lower portion dark brown, 1.4–2.1 × 0.6–0.9 mm, coarsely papillose. 2n = 14.

Distribution

w United States, nw Mexico.

Discussion

Subspecies 6 (6 in the flora).

P. H. Raven (1969) included within Eremothera boothii a complex of intergrading entities that have been variously treated, ranging from three species with infraspecific taxa to one species with infraspecific taxa. Raven determined E. boothii to be self-incompatible.

Selected References

None.

Key

1 Cluster of basal leaves prominent at time of flowering; plants blooming February through June (or August), strigillose and/or glandular puberulent. > 2
2 Capsules 2–3.8 mm diam. near base, thickened and indurate along angles, curved outward but not downward; inflorescences very dense. Eremothera boothii subsp. condensata
2 Capsules 1–2.3 mm diam. near base, not thickened and indurate, curved outward or downward; inflorescences ± open. > 3
3 Capsules 1.7–2.3 mm diam. near base, curved outward. Eremothera boothii subsp. decorticans
3 Capsules 1–1.6 mm diam. near base, apex often curved downward. Eremothera boothii subsp. desertorum
1 Cluster of basal leaves rarely prominent at time of flowering, leaves evenly distributed; plants blooming May through August (or September), villous and/or glandular puberulent, rarely (subsp. alyssoides) densely strigillose. > 4
4 Herbs usually strigillose, often densely so, rarely villous and/or glandular puberulent; plants flowering May through June (or August). Eremothera boothii subsp. alyssoides
4 Herbs villous and glandular puberulent; plants flowering (May to) June through August (or September). > 5
5 Herbs villous, also glandular puberulent, especially in inflorescences; stems usually 15–60 cm; leaf blades narrowly lanceolate, narrowly ovate, or ovate to elliptic, 0.6–2.2 cm wide, margins coarsely serrulate to sinuate-toothed. Eremothera boothii subsp. boothii
5 Herbs densely villous, also densely glandular puberulent, especially in inflorescences; stems 5–20 cm; leaf blades narrowly elliptic to narrowly lanceolate or lanceolate, sometimes oblanceolate proximally, 0.3–1.5 cm wide, margins sparsely serrulate to sometimes sinuate-toothed. Eremothera boothii subsp. intermedia