Epilobium minutum |
Onagraceae |
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California willowherb, chaparral willowherb, desert willowherb, little willowherb, minute willowherb, small-flower willowherb |
evening-primrose family |
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Habit | Herbs slender. | Herbs, annual or perennial, shrubs, or subshrubs, [lianas or trees], terrestrial, amphibious, or aquatic, unarmed, not clonal; often with epidermal oil cells, usually with internal phloem, abundant raphides in vegetative cells. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Stems | strict, erect, sometimes reddish green, terete, 3.5–40 cm, simple or freely branched, subglabrous proximally to strigillose and glandular puberulent distally. |
erect to decumbent or prostrate. |
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Leaves | alternate distally, not fasciculate, petiole 0–2 mm, blade subspatulate proximally to lanceolate, oblanceolate, or narrowly elliptical distally, not folded along midrib, 0.9–2.5 × 0.2–0.6 cm, shorter than internodes, base tapered, margins entire or scarcely denticulate, 1–4 teeth per side, lateral veins obscure, apex subacute or often blunt proximally, surfaces subglabrous or with scattered hairs along margins; bracts much reduced, sometimes attached to pedicel. |
usually deciduous, usually alternate or opposite, sometimes whorled, simple, usually cauline, sometimes basal and forming rosettes; stipules present, intrapetiolar, usually caducous, relatively small, or absent (tribes Epilobieae and Onagreae); sessile or subsessile to petiolate; blade margins usually entire, toothed, or pinnately lobed, rarely bipinnately lobed. |
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Inflorescences | erect racemes or open panicles, relatively loose and uncrowded, branches thin, mixed strigillose and glandular puberulent. |
axillary, flowers solitary, leafy spikes, racemes, or panicles. |
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Flowers | erect or, sometimes, nodding in bud; buds broadly ovoid, 1.2–2.5 × 1–1.5 mm; floral tube 1.1–1.5 × 1–1.4 mm, usually with ring of spreading hairs at mouth inside; sepals 0.5–2.5 × 0.4–1.3 mm, apex acute, abaxial surface strigillose, sometimes mixed glandular puberulent; petals white to pink, 2–5 × 1.5–3 mm, apical notch 0.2–1.9 mm; filaments white, those of longer stamens 0.5–3 mm, those of shorter ones 0.3–2 mm; anthers 0.6–1 × 0.5–0.8 mm; ovary 4–9 mm, mixed strigillose and glandular puberulent; style light pink, 1–3.5 mm, stigma subclavate to obscurely 4-lobed, 0.4–0.6 × 0.4–0.5 mm, surrounded by longer anthers. |
usually bisexual, (protandrous in Chamaenerion, Clarkia, Epilobium, [and most species of Lopezia]; protogynous in Circaea and Fuchsia), sometimes unisexual (gynodioecious or dioecious, [subdioecious]), usually actinomorphic, sometimes zygomorphic, (2–)4(–7)-merous; perianth and androecium epigynous; sepals persistent after anthesis (in Ludwigia), or all flower parts deciduous after anthesis; floral tube present or absent in Chamaenerion, Ludwigia, [and most species of Lopezia]; sepals usually green or red, rarely pink or purple, valvate; petals present, rarely absent, often fading darker with age, imbricate or convolute, sometimes clawed; nectary present; stamens 2 times as many as sepals and in 2 series, antisepalous set usually longer, rarely all equal (Chamaenerion), or as many as sepals, [in Lopezia reduced to 2 or 1 plus 1 sterile staminode]; filaments distinct; anthers usually versatile, sometimes basifixed, dithecal, polysporangiate, with tapetal septa, sometimes also with parenchymatous septa, opening by longitudinal slits, pollen grains united by viscin threads, (2 or)3(–5)-aperturate, shed singly or in tetrads or polyads; ovary inferior, usually with as many carpels and locules as sepals, rarely 1 or 2 (Circaea and Gayophytum), septa sometimes thin or absent at maturity; placentation axile or parietal; style 1, stigma 1, with as many lobes as sepals or clavate to globose, papillate or not, and wet with free-running secretions to dry without the secretions; ovules 1 to numerous per locule, in 1 or several rows or clustered, anatropous, bitegmic. |
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Fruit | a loculicidal capsule or indehiscent berry or nutlike. |
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Capsules | 9–28 mm, surfaces strigillose and glandular puberulent; pedicel 3–10 mm. |
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Seeds | obovoid, without constriction, 0.9–1.2 × 0.4–0.6 mm, low chalazal collar 0.1–0.2 mm wide, brown, surface reticulate; coma easily detached, white, 2.5–3 mm. |
smooth or sculptured, sometimes with a coma or wings, with straight, oily embryo, 4-nucleate embryo sac, endosperm absent. |
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2n | = 26. |
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Epilobium minutum |
Onagraceae |
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Phenology | Flowering Apr–Sep. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Habitat | Open, dry places, along roads, disturbed areas. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Elevation | 90–1900 m. (300–6200 ft.) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Distribution |
CA; ID; MT; NV; OR; WA; BC
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North America; Mexico; Central America; South America; West Indies; Bermuda; Eurasia; Africa; Atlantic Islands; Indian Ocean Islands; Pacific Islands; Australasia; nearly worldwide; primarily New World |
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Discussion | Epilobium minutum, like the similar E. foliosum, also occasionally produces cleistogamous flowers, and is modally autogamous in any event. S. R. Seavey et al. (1977b) observed that E. minutum is less common than E. foliosum in the southern part of their overlapping ranges and more common in the north. Several sheets (for example, Lawler 3276, California, Butte Co. [MO]; Nelson & Gordon 5573, California, Trinity Co. [MO]) mention that the plants were growing on serpentine soil. The earliest collection of this species appears to be one made by Archibald Menzies in 1792–1794 under the name E. palustre (BM). Crossostigma lindleyi Spach (a substitute name for Epilobium minutum) and E. lindleyi (Spach) Rydberg are illegitimate names that pertain here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Genera 22, species 664 (17 genera, 277 species in the flora). Members of the Onagraceae are especially richly represented in North America. The family comprises annual and perennial herbs, with some shrubs and a few small to medium-sized trees. Most species occur in open habitats, ranging from dry to wet, with a few species of Ludwigia aquatic, from the tropics to the deserts of western North America, temperate forests, and arctic tundra; some species of Epilobium, Ludwigia, and Oenothera can be weeds in disturbed habitats. Members of the family are characterized by 4-merous flowers (sometimes 2-, 5-, or 7-merous), an inferior ovary, a floral tube in most species, stamens usually two times as many as sepals, and pollen connected by viscin threads. Flowers are usually bisexual, sometimes unisexual, and plants are gynodioecious, matinal, diurnal, or vespertine, self-compatible or self-incompatible, often outcrossing and then pollinated by a wide variety of insects or birds, or autogamous (P. H. Raven 1979; W. L. Wagner et al. 2007). Onagraceae are known in considerable systematic detail, and information is available on comparative breeding systems and pollination biology, on chromosome numbers and cytogenetic relations, often involving translocations, and on vegetative, floral, and seed anatomy, palynology, and embryology. The phylogeny of the family is known in reasonably good detail, with most parts of the trees generally well-supported. The suprageneric and generic classification presented by W. L. Wagner et al. (2007) differs in a number of ways from the previous classification (P. H. Raven 1979, 1988). Onagraceae are divided into two subfamilies based on a fundamental basal split recognized in all phylogenetic studies (R. H. Eyde 1981; P. C. Hoch et al. 1993; R. A. Levin et al. 2003, 2004; V. S. Ford and L. D. Gottlieb 2007), with Ludwigia on one branch (as Ludwigioideae), and the rest of the family on a second branch (as Onagroideae). Onagroideae are subdivided into six tribes: Circaeeae (including Fuchsieae), Epilobieae, Gongylocarpeae, Hauyeae, Lopezieae, and Onagreae. The Epilobieae and Onagreae are diverse; together they constitute fully two-thirds of the species in the family and include 15 of the 22 genera. The classification following Wagner et al. can be viewed on the Onagraceae web site by Wagner and Hoch at http://botany.si.edu/Onagraceae. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 10. | FNA vol. 10. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Parent taxa | Onagraceae > subfam. Onagroideae > tribe Epilobieae > Epilobium > sect. Crossostigma | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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Synonyms | E. minutum var. canescens | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Name authority | Lindley in W. J. Hooker: Fl. Bor.-Amer. 1: 207. (1832) | Jussieu | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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