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Vascular Plants of California
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Frangula rubra

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: FrangulaView DescriptionDichotomous Key

Habit: Shrub, small tree. Stem: branches alternate, flexible; winter bud scales 0. Leaf: scattered along branches or clustered on short-shoots, deciduous or not; stipules generally deciduous; petioled; blade veins prominent or not. Inflorescence: umbel or flowers 1 in axils. Flower: bisexual; hypanthium 1--3 mm wide, cup-shaped; sepals 5, erect, fleshy, keeled adaxially; petals 5, short-clawed; stamens 5; disk thin, adherent to hypanthium; ovary +- inferior, chambers 2--3, 1--2-ovuled, stigma 2--3-lobed. Fruit: drupe, 2--3[4]-stoned.
Species In Genus: 50 species: temperate, w. Med, Eurasia. Etymology: (Frangible: capable of being broken) Note: Often a subg. of Rhamnus; some of value in food, medicine.
eFlora Treatment Author: John O. Sawyer, Jr.
Reference: Sawyer & Edwards 2007 Madroño 54:172--174
Unabridged Reference: Bolmgren & Oxelman 2004 Taxon 53:383--390; Wolf 1938 Rancho Santa Ana Bot Gard Monogr 1.
Frangula rubra (Greene) Grubov
Habit: Shrub, < 2 m. Stem: bark red to bright gray; twigs red to gray; terminal bud hairy. Leaf: generally scattered along stem, deciduous; petiole 2--12 mm; blade 15--80 mm, narrowly elliptic to obovate, thin, green or gray, generally glabrous to finely hairy or abaxially puberulent on midrib, veins, acute to rounded at base, tip, margin finely toothed to entire, veins not prominent. Inflorescence: 4--15-flowered; pedicel 1--12 mm. Flower: hypanthium 2 mm wide. Fruit: 2(3)-stoned, 12 mm, black.
Note: 1 other subsp., in Nevada.
Synonyms: Rhamnus rubra Greene
Unabridged Synonyms: Rhamnus californica var. rubra (Greene) Trel.; Rhamnus californica var. obtusissima (Greene) Jeps., in part, misappl.
Unabridged Note: Frangula rubra subsp. nevadensis (A. Nelson) Kartesz & Gandhi in Nevada. The Frangula rubra complex is a group of closely related plants that needs study. In NV they reach only Douglas and Washoe counties. C.B. Wolf's descriptions (1938) provide only a single distinct character to separate the subspecies, but field and herbarium study argue for the recognition of infraspecific taxa even with the intermediates and variants. The range of Frangula rubra subsp. obtusissima, in central SN, is central, and Wolf reported "intergradations in various degrees" between it and all the other subspecies. Furthermore, Frangula rubra subsp. yosemitana and Frangula californica subsp. cuspidata grow along the east side of SN and can be easily confused. Plants of both taxa can be deciduous, but Wolf noted differences in pubescence and in leaf margin characters to differentiate the 2, although both are variable throughout their ranges.
Jepson eFlora Author: John O. Sawyer, Jr.
Reference: Sawyer & Edwards 2007 Madroño 54:172--174
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)

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Botanical illustration including Frangula rubra

botanical illustration including Frangula rubra


Citation for this treatment: John O. Sawyer, Jr. 2012, Frangula rubra, in Jepson Flora Project (eds.) Jepson eFlora, /eflora/eflora_display.php?tid=26044, accessed on March 03, 2021.

Citation for the whole project: Jepson Flora Project (eds.) 2021, Jepson eFlora,, accessed on March 03, 2021.

Frangula rubra
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© 2009 Keir Morse
Frangula rubra
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© 2010 Barry Breckling
Frangula rubra subsp. obtusissima
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© 2019 Steve Matson
Frangula rubra
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© 2017 Vernon Smith
Frangula rubra
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© 2005 Steve Matson
Frangula rubra
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© 2005 Steve Matson

More photos of Frangula rubra in CalPhotos

Geographic subdivisions for Frangula rubra:
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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.
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).