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Osmorhiza occidentalis

Higher Taxonomy
Family: ApiaceaeView DescriptionDichotomous Key

Habit: Annual to perennial herb [shrub, tree], generally from taproot. Stem: generally +- scapose, generally ribbed, hollow. Leaf: basal and generally cauline, generally alternate; stipules generally 0; petiole base generally sheathing stem; blade generally much dissected, occasionally compound. Inflorescence: umbel or head, simple or compound, generally peduncled; bracts present in involucres or 0; bractlets generally present in "involucels". Flower: many, small, generally bisexual (or some staminate), generally radial (or outer bilateral); calyx 0 or lobes 5, small; petals 5, free, generally ovate or spoon-shaped, generally incurved at tips, generally +- ephemeral; stamens 5; pistil 1, ovary inferior, 2-chambered, generally with a +- conic, persistent projection or platform at tip subtending 2 free styles. Fruit: 2 dry, 1-seeded halves (= mericarps), separating from each other but generally +- persistent to central axis; ribs on halves 5, 2 marginal, 3 to back; oil tubes 1--several per interval between ribs.
Genera In Family: 300 genera, 3000 species: +- worldwide, especially temperate; many cultivated for food or spice (e.g., Carum, caraway; Daucus; Petroselinum); Bupleurum lancifolium Hornem. is historical garden weed; some toxic (e.g., Conium). Note: Mature fruit generally critical in identification, shape given in outline. Hydrocotyle moved to Araliaceae. Petroselinum crispum (Mill.) A.W. Hill is a waif.
eFlora Treatment Author: Lincoln Constance & Margriet Wetherwax, except as noted
Scientific Editor: Douglas H. Goldman, Bruce G. Baldwin.
Genus: OsmorhizaView DescriptionDichotomous Key

Habit: Perennial herb, +- glabrous to hairy; roots thick, clustered, licorice-scented. Stem: branched, leafy. Leaf: blade oblong to triangular-ovate, 2-pinnate or ternate-pinnate or 2--3-ternate, leaflets lanceolate to round. Inflorescence: umbels compound; bracts 0; bractlets 0--several, conspicuous; rays, pedicels few, spreading-ascending to spreading. Flower: calyx lobes 0; petals obovate, white, purple, or +- green-yellow (+- green-white), tips narrowed; disk occasionally present. Fruit: linear to oblong, cylindric to club-shaped, +- compressed side-to-side, bristly to glabrous; base obtuse or long-tapered into tail, tip tapered into beak or obtuse; ribs thread-like; oil tubes obscure; fruit axis divided in distal 1/2. Seed: face concave or grooved.
Species In Genus: +- 10 species: America, eastern and southern Asia. Etymology: (Greek: sweet root)
Reference: [Lowry & Jones 1985 Ann Missouri Bot Gard 71:1128--1171]

Osmorhiza occidentalis (Nutt.) Torr.
Habit: Plant 4--12 dm, glabrous to sparsely fine-hairy. Leaf: petiole 5--25 cm; blade 1--2 dm, oblong to ovate, 2-pinnate, leaflets 2--10 cm, lance-oblong to ovate, serrate and generally irregularly cut or lobed. Inflorescence: peduncle 6--20 cm; bractlets generally 0; rays 5--12, generally 3--8 cm, ascending to spreading-ascending; pedicels 3--8 mm. Flower: corolla yellow; styles 0.8--1.4 mm; disk conspicuous. Fruit: 12--22 mm, linear-fusiform, not long-tapered at base; tail 0; tip narrowed proximal to beak; ribs (and intervals) glabrous. Chromosomes: 2n=22.
Ecology: Conifer forest, oak woodland; Elevation: 200--3200 m. Bioregional Distribution: KR, NCoR, CaRH, n&c SNH, MP, n SNE; Distribution Outside California: to western Canada, Colorado. Flowering Time: May--Jul
eFlora Treatment Author: Lincoln Constance & Margriet Wetherwax
Reference: [Lowry & Jones 1985 Ann Missouri Bot Gard 71:1128--1171]
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botanical illustration including Osmorhiza occidentalis


Citation for this treatment: Lincoln Constance & Margriet Wetherwax 2012, Osmorhiza occidentalis, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on December 12, 2017.

Citation for the whole project: Jepson Flora Project (eds.) 2017, Jepson eFlora,, accessed on December 12, 2017.

Osmorhiza occidentalis
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© 2006 Steve Matson
Osmorhiza occidentalis
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© 2015 Barry Breckling
Osmorhiza occidentalis
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© 2009 Barry Breckling
Osmorhiza occidentalis
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© 2008 Keir Morse
Osmorhiza occidentalis
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© 2008 Keir Morse
Osmorhiza occidentalis
click for enlargement
© 2015 Barry Breckling

More photos of Osmorhiza occidentalis in CalPhotos

Geographic subdivisions for Osmorhiza occidentalis:
KR, NCoR, CaRH, n&c SNH, MP, n SNE;
Markers link to CCH specimen records. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues. Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
map of distribution 1
(Note: any qualifiers in the taxon distribution description, such as 'northern', 'southern', 'adjacent' etc., are not reflected in the map above, and in some cases indication of a taxon in a subdivision is based on a single collection or author-verified occurence).

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Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.