Jepson eFlora: Taxon page
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Ceanothus papillosus

Higher Taxonomy
Family: RhamnaceaeView DescriptionDichotomous Key

Habit: [Perennial herb] shrub, tree, generally erect, often thorny. Leaf: simple, generally alternate, often clustered on short-shoots; stipules generally present, occasionally modified into spines; generally petioled; blade pinnate-veined or 1--5-ribbed from base. Inflorescence: cyme, panicle, umbel, or flowers 1 or clustered in axils or on short-shoots. Flower: generally bisexual, radial; hypanthium subtending, surrounding, or partly fused to ovary; sepals 4--5; petals 0, 4--5, generally clawed; stamens 0, 4--5, alternate sepals, attached to hypanthium top, each generally fitting into a petal concavity; disk (0 or) between stamens, ovary, thin to fleshy, entire or lobed, free from ovary, adherent or fused to hypanthium; ovary superior or +- inferior, chambers [1]2--4, 1--2-ovuled, style 1, stigma entire or 2--3-lobed. Fruit: capsule, drupe.
Genera In Family: 50--52 genera, 950 species: especially tropics, subtropics some cultivated (Ceanothus; Frangula; Rhamnus; Ziziphus).
eFlora Treatment Author: John O. Sawyer, Jr., except as noted
Scientific Editor: Steve Boyd, Thomas J. Rosatti.
Genus: CeanothusView DescriptionDichotomous Key

Habit: Shrub, tree-like or not, generally erect or mat- to mound-like. Stem: branches generally arranged like leaves; twigs thorn-like or not, generally not angled. Leaf: alternate or opposite, some clustered on short-shoots or not, deciduous or evergreen; stipules scale-like, thin, deciduous, or knob-like, corky, thick, base persistent; blade flat or wavy, tip generally acute to obtuse, margin thick (i.e., thicker than adjacent blade) or not, rolled under or not, wavy or not, entire or gland- or sharp-toothed, glands generally dark, teeth pale, alternate blade 1--3-ribbed from base, generally thin, opposite blade 1-ribbed from base, thick, firm. Inflorescence: umbel-, raceme-, or panicle-like aggregations of few-flowered clusters, axillary or terminal; pedicels white to deep blue or pink. Flower: conspicuous, generally < 5 mm; hypanthium surrounding fleshy disk below ovary base, in fruit thick, not splitting; sepals generally 5, lance-deltate, incurved, colored like petals, persistent; petals generally 5, blade hood-like, white to deep blue or pink; stamens generally 5, opposite petals; ovary 1/2-inferior, 3-lobed, chambers 3, each 1-ovuled, styles 3. Fruit: capsule, +- spheric, generally +- 3-lobed, generally smooth, 3-ridged or not, horned or not. Seed: 3, 2--5 mm.
Species In Genus: +- 55 species: North America. Etymology: (Greek: thorny pl) Note: Hybrids common (named hybrids not recognized here), discussed in Fross & Wilken; hybrid forms do not key easily. As recircumscribed here, Ceanothus greggii A. Gray restricted to Mexico.
eFlora Treatment Author: Dieter H. Wilken

Ceanothus papillosus Torr. & A. Gray
Habit: Plant erect, occasionally mound-like, +- dense, 1--3.5 m. Stem: ascending to erect; twigs flexible, not thorn-like, green to gray-brown. Leaf: alternate, evergreen; stipules scale-like; petiole 1--3 mm; blade 11--50 mm, 6--15 mm wide, oblong to narrowly elliptic, flat, thick, adaxially dark green, not furrowed, glandular-papillate, abaxially paler, generally densely hairy, 1-ribbed from base, tip +- obtuse to notched, margin rolled under, minutely gland-toothed, teeth 17--31, glands spheric. Inflorescence: raceme-like, 2--6 cm. Flower: deep blue. Fruit: 2--3 mm, sticky, +- ridged distally; horns 0. Chromosomes: 2n=24.
Ecology: Open sites, chaparral, woodland; Elevation: 90--1500 m. Bioregional Distribution: SnFrB, SCoR, WTR, nw PR; Distribution Outside California: northern Baja California. Flowering Time: Mar--May Note: Were they to be recognized taxonomically, mound-like plants with arched stems from western WTR would be assignable to Ceanothus papillosus var. roweanus McMinn; study needed.
eFlora Treatment Author: Dieter H. Wilken
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botanical illustration including Ceanothus papillosus


Citation for this treatment: Dieter H. Wilken 2016. Ceanothus papillosus, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on April 29, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora,, accessed on April 29, 2016.

Ceanothus papillosus
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© 2009 Neal Kramer
Ceanothus papillosus
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© 2015 Aaron E. Sims and CNPS
Ceanothus papillosus
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© 2006 Steve Matson
Ceanothus papillosus
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© 2004 Robert E. Preston, Ph.D.
Ceanothus papillosus
click for enlargement
© 2015 Aaron E. Sims and CNPS
Ceanothus papillosus
click for enlargement
© 2006 Steve Matson

More photos of Ceanothus papillosus in CalPhotos

Geographic subdivisions for Ceanothus papillosus:
SnFrB, SCoR, WTR, nw PR;
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.