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Vascular Plants of California
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Arctostaphylos osoensis

Higher Taxonomy
Family: EricaceaeView DescriptionDichotomous Key

Habit: Perennial herb, shrub, tree. Stem: bark often peeling distinctively. Leaf: simple or 0, generally cauline, alternate, opposite (whorled), evergreen or deciduous, often leathery, petioled or not; stipules 0. Inflorescence: raceme, panicle, cyme, or flowers 1, terminal or axillary, generally bracted; pedicel often with 2 bractlets. Flower: generally bisexual, generally radial, bell-shaped, cylindric, or urn-shaped; sepals generally (0)4--5, generally free; petals generally (0)4--5, free or fused; stamens (2--5)8--10, free, filaments rarely appendaged, anthers dehiscing by pores or slits, awns 0 or 2(4), seemingly abaxial, reduced or elongate, generally curved; nectary generally present at ovary base, generally disk-like; ovary superior or inferior, chambers generally 1--5, placentas axile or parietal, ovules 1--many per chamber, style 1, stigma head- to funnel-like or lobed. Fruit: capsule, drupe, berry. Seed: generally many, winged or not.
Genera In Family: +- 100 genera, 3000 species: generally worldwide except deserts; some cultivated, especially Arbutus, Arctostaphylos, Rhododendron, Vaccinium. Note: Monophyletic only if Empetraceae included, as treated here. Ledum included in Rhododendron. Non-green plants obtain nutrition from green plants through fungal intermediates.
eFlora Treatment Author: Gary D. Wallace, except as noted
Scientific Editor: Gary D. Wallace, Thomas J. Rosatti, Bruce G. Baldwin.
Arctostaphylos osoensis P.V. Wells
Habit: Erect, 1--4 m. Stem: old stem bark persistent, gray, shredding (smooth); twig (and nascent inflorescence axis) sparsely short-nonglandular-hairy. Leaf: overlapped; petiole < 2 mm; blade 1.5--3 cm, 1.5--2.5 cm wide, ovate to round-ovate, dark green, +- shiny, sparsely short-nonglandular-hairy or glabrous, base deeply lobed, clasping, tip obtuse, margin entire, flat. Inflorescence: +- raceme, 0--1-branched; nascent inflorescence pendent, axis 0.5--1 cm, > 1 mm wide; bracts 4--8 mm, leaf-like, lanceolate to ovate, glabrous; pedicel 8--9 mm, glabrous. Flower: ovary glabrous. Fruit: 5--8 mm wide, depressed-spheric, glabrous; stones free. Chromosomes: 2n=26.
Ecology: Dacite (volcanic) outcrops, chaparral; Elevation: 50--375 m. Bioregional Distribution: s CCo (w Los Osos Valley, San Luis Obispo Co.). Flowering Time: Dec--Feb
Jepson eFlora Author: V. Thomas Parker, Michael C. Vasey & Jon E. Keeley
Reference: Keeley 1997 Madroño 44:109--111; Parker et al. 2007 Madroño 54:148--155
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)
Listed on CNPS Rare Plant Inventory

Previous taxon: Arctostaphylos ohloneana
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Citation for this treatment: V. Thomas Parker, Michael C. Vasey & Jon E. Keeley 2012, Arctostaphylos osoensis, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on October 03, 2023.

Citation for the whole project: Jepson Flora Project (eds.) 2023, Jepson eFlora,, accessed on October 03, 2023.

Arctostaphylos osoensis
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© 2004 David Graber
Arctostaphylos osoensis
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© 2004 David Graber
Arctostaphylos osoensis
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© 2004 David Graber
Arctostaphylos osoensis
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© 2004 David Graber
Arctostaphylos osoensis
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© 2011 David Graber
Arctostaphylos osoensis
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© 2012 John Game

More photos of Arctostaphylos osoensis in CalPhotos

Geographic subdivisions for Arctostaphylos osoensis:
s CCo (w Los Osos Valley, San Luis Obispo Co.).
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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).


Data provided by the participants of the  Consortium of California Herbaria.
View all CCH records
All markers link to CCH specimen records. The original determination is shown in the popup window.
Blue markers indicate specimens that map to one of the expected Jepson geographic subdivisions (see left map). Purple markers indicate specimens collected from a garden, greenhouse, or other non-wild location.
Yellow markers indicate records that may provide evidence for eFlora range revision or may have georeferencing or identification issues.

CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa, if there are more than 1 infraspecific taxon in CA.
Blue line denotes eFlora flowering time (fruiting time in some monocot genera).