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Horkelia tridentata var. flavescens

Higher Taxonomy
Family: RosaceaeView DescriptionDichotomous Key

Common Name: ROSE FAMILY
Habit: Annual to tree, glandular or not. Leaf: simple to palmately or pinnately compound, generally alternate; stipules free to fused (0), persistent to deciduous. Inflorescence: cyme, raceme, panicle, cluster, or flowers 1; bractlets on pedicel ("pedicel bractlets") generally 0--3(many), subtended by bract or generally not. Flower: generally bisexual, radial; hypanthium free or fused to ovary, saucer- to funnel-shaped, subtending bractlets ("hypanthium bractlets") 0--5, alternate sepals; sepals generally 5; petals generally 5, free; stamens (0,1)5--many, anther pollen sacs generally 2; pistils (0)1--many, simple or compound, ovary superior to inferior, styles 1--5. Fruit: 1--many per flower, achene (fleshy-coated or not), follicle, drupe, or pome with generally papery core, occasionally drupe-like with 1--5 stones. Seed: generally 1--5 (per fruit, not per flower).
Genera In Family: 110 genera, +- 3000 species: worldwide, especially temperate; many cultivated for ornamental, fruit, especially Cotoneaster, Fragaria, Malus, Prunus, Pyracantha, Rosa, Rubus. Note: Number of teeth is per leaf or leaflet, not per side of leaf or leaflet, except in Drymocallis.
eFlora Treatment Author: Daniel Potter & Barbara Ertter, family description, key to genera; treatment of genera by Daniel Potter, except as noted
Scientific Editor: Daniel Potter, Thomas J. Rosatti.
Genus: HorkeliaView DescriptionDichotomous Key

Habit: Perennial herb, generally +- glandular, generally resinous-smelling; caudex generally branched. Stem: generally ascending to erect. Leaf: generally basal, odd-1-pinnately compound, generally +- flat; cauline alternate, reduced upward; leaflets 2--15 per side, uppermost lateral generally +- fused with terminal. Inflorescence: cyme; pedicels generally straight, bractlets 0. Flower: hypanthium cup-like, +- flat-bottomed, width +- 2 × length, bractlets 5, generally 2/3 sepals; sepals often reflexed; petals generally +- = sepal, blunt, white; stamens 10, filaments +- flat, often forming a tube; pistils 2--many, ovary superior, style attached below fruit tip, +- thicker at base. Fruit: achene.
Species In Genus: 20 species: western North America. Etymology: (J. Horkel, German plant physiologist, 1769--1846) Note: Many attractive to bees; data apply to basal leaves, pressed hypanthia.
eFlora Treatment Author: Barbara Ertter
Species: Horkelia tridentataView Description 

Habit: Plant rosetted or tufted, +- gray, +- odorless; caudex 0--few-branched. Stem: < 45 cm, +- glabrous to sparsely glandular above. Leaf: 3--12 cm; stipules entire to forked; leaflets 2--5 per side, separated, 5--30 mm, generally elliptic to oblong, +- 3-toothed < 1/4 to base (entire), at least lower surface +- densely hairy. Inflorescence: clusters +- head-like, generally 3--40-flowered; pedicels generally 1--6 mm. Flower: hypanthium width 1--2 × length, bractlets < 0.5 mm wide, linear; sepals generally 1.5--3 mm; petals 1.5--4 mm; filament base generally +- 0.2--0.5 mm wide, anthers 0.2--0.5 mm; pistils 5--15, style 1--2.5 mm.
Note: Varieties intergrade extensively.

Horkelia tridentata var. flavescens (Rydb.) Ertter & Reveal
Stem: decumbent. Inflorescence: cluster generally 1. Flower: 6--10 mm wide; hypanthium 2.5--5 mm wide, inner wall hairy (except in NCoRH); petals often < sepal, +- widely oblanceolate; filaments 1--2 mm. Fruit: 2--2.5 mm.
Ecology: Often on +- serpentine; Elevation: 750--2000 m. Bioregional Distribution: KR, NCoR, n SNH (esp Plumas Co.); Distribution Outside California: southwestern Oregon. Flowering Time: Apr--Jul Note: NCoRH plants may be distinct.
Synonyms: Horkelia flavescens Rydb; Horkelia tridentata subsp. flavescens (Rydb.) D.D. Keck
eFlora Treatment Author: Barbara Ertter
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Citation for this treatment: Barbara Ertter 2016. Horkelia tridentata var. flavescens, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on May 02, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora,, accessed on May 02, 2016.

Horkelia tridentata var. flavescens
click for enlargement
© 2014 Julie Kierstead Nelson
Horkelia tridentata var. flavescens
click for enlargement
© 2014 Julie Kierstead Nelson

More photos of Horkelia tridentata var. flavescens in CalPhotos

Geographic subdivisions for Horkelia tridentata var. flavescens:
KR, NCoR, n SNH (esp Plumas Co.);
Markers link to CCH specimen records. If the markers are obscured, reload the page [or change window size and reload]. Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.
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.