Jepson eFlora: Taxon page
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Horkelia howellii
HOWELL'S HORKELIA

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

Horkelia howellii (Greene) Rydb.
NATIVE
Habit: Plant +- tufted, +- green; odor indistinct; caudex few-branched. Stem: 15--50 cm; hairs at base +- 1 mm. Leaf: 5--15 cm, often +- cylindric; stipules forked to pinnately divided; leaflets +- 15 per side, +- crowded, 3--10 mm, generally lobed +- 1/2 to base, lobes < 10, elliptic, hairs few to many. Inflorescence: open; flowers many, +- separate or in few-flowered clusters; pedicels generally 1--4 mm. Flower: hypanthium 2--3 mm wide, 1--2 × length, bractlets +- 0.5 mm wide, lance-linear; sepals 2.5--4 mm; petals 3--5 mm, narrow-obcordate, often pink-tinged; filaments 1--1.5 mm, base +- 0.5 mm wide, anthers +- 0.5 mm; pistils 2--6, style +- 1.5--2 mm. Fruit: 2--2.7 mm.
Ecology: Dry, rocky serpentine clay, open chaparral or pine forest; Elevation: 60--1200 m. Bioregional Distribution: w KR; Distribution Outside California: southwestern Oregon. Flowering Time: Jun--Aug Note: Previously included in Horkelia sericata.
eFlora Treatment Author: Barbara Ertter
Jepson Online Interchange
Listed on CNPS Rare Plant Inventory

Previous taxon: Horkelia hispidula
Next taxon: Horkelia marinensis

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botanical illustration including Horkelia howellii

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Citation for this treatment: Barbara Ertter 2016. Horkelia howellii, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=91756, accessed on September 29, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on September 29, 2016.


Geographic subdivisions for Horkelia howellii:
w KR;
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.
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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.