Common Name: BUCKTHORN FAMILY 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.
Ceanothus sonomensis J.T. Howell
NATIVE Habit: Plant erect, +- open, < 1.5 m. Stem: ascending to erect, not rooting at nodes; twigs not angled; gray to brown. Leaf: opposite, evergreen, +- spreading; stipules knob-like; petiole < 1 mm; blade generally 5--11 mm, 2--5 mm wide, obovate to round, adaxially shiny green, glabrous, abaxially gray, minutely appressed-tomentose, especially veins, tip notched, margin thick, teeth 3--5, +- spine-like. Inflorescence: umbel-like, +- 1 cm. Flower: blue or lavender. Fruit: 4--5 mm wide; horns 2--3 mm, slender. Chromosomes: 2n=24. Ecology: Serpentine or volcanic substrates, chaparral; Elevation: 140--600 m. Bioregional Distribution: NCoRO (Hood Mtn region, Sonoma and Napa cos.). Flowering Time: Mar--Apr Note: Occasionally confused with Ceanothus divergens. Jepson eFlora Author: Dylan O. Burge & Dieter H. Wilken Reference: Fross & Wilken 2006 Ceanothus. Timber Press; Burge et al. 2015 Syst Bot 40:950--961. Index of California Plant Names (ICPN; linked via the Jepson Online Interchange) Listed on CNPS Rare Plant Inventory Previous taxon: Ceanothus sanguineus Next taxon: Ceanothus spinosus
Botanical illustration including Ceanothus sonomensis
Citation for this treatment: Dylan O. Burge & Dieter H. Wilken 2020, Ceanothus sonomensis, in Jepson Flora Project (eds.) Jepson eFlora, Revision 8, https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=18437, accessed on October 03, 2023.
Citation for the whole project: Jepson Flora Project (eds.) 2023, Jepson eFlora, https://ucjeps.berkeley.edu/eflora/, accessed on October 03, 2023.
Geographic subdivisions for Ceanothus sonomensis:
NCoRO (Hood Mtn region, Sonoma and Napa cos.).
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(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.
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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.
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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).
