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Vascular Plants of California
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Robinia pseudoacacia

Higher Taxonomy
Family: Fabaceae (Leguminosae)View DescriptionDichotomous Key
Habit: Annual to tree. Leaf: generally alternate, generally compound, generally stipuled, generally entire, pinnately veined Inflorescence: generally raceme, spike, umbel or head; or flowers 1--few in axils. Flower: generally bisexual, generally bilateral; hypanthium 0 or flat to tubular; sepals generally 5, generally fused; petals generally 5, free, fused, or lower 2 +- united into keel (see 3, Key to Groups, for banner, wings); stamens 10 or many (or [1], 5, 6, 7, 9), free or fused or 10 with 9 filaments at least partly fused, 1 (uppermost) free; pistil 1, ovary superior, generally 1-chambered, ovules 1--many, style, stigma 1. Fruit: legume, including a stalk-like base (above receptacle) or not. Seed: 1--many, often +- reniform, generally hard, smooth.
Genera In Family: +- 730 genera, 19400 species: worldwide; with grasses, requisite in agriculture, most natural ecosystems. Many cultivated, most importantly Arachis, peanut; Glycine, soybean; Phaseolus, beans; Medicago, alfalfa; Trifolium, clovers; many orns. Note: Unless stated otherwise, fruit length including stalk-like base, number of 2° leaflets is per 1° leaflet. Upper suture of fruit adaxial, lower abaxial. Anthyllis vulneraria L. evidently a waif, a contaminant of legume seed from Europe. Laburnum anagyroides Medik., collected on Mount St. Helena in 1987, may be naturalized. Ceratonia siliqua L., carob tree (Group 2), differs from Gleditsia triacanthos L. in having evergreen (vs deciduous) leaves that are 1-pinnate (vs 1-pinnate on spurs on old stems, 2-pinnate on new stems) with 2--5(8) (vs 7--17) 1° leaflets, commonly cultivated, now naturalized in southern California. Aeschynomene rudis Benth. , Halimodendron halodendron (Pall.) Voss (possibly extirpated), Lens culinaris Medik. are agricultural weeds. Caragana arborescens Lam. only cult. Ononis alopecuroides L. , Sphaerophysa salsula (Pall.) DC. all evidently extirpated. Cercidium moved to Parkinsonia; Chamaecytisus to Cytisus; Psoralidium lanceolatum to Ladeania.
eFlora Treatment Author: Martin F. Wojciechowski, except as noted
Scientific Editor: Martin F. Wojciechowski, Thomas J. Rosatti.
Genus: RobiniaView DescriptionDichotomous Key

Common Name: LOCUST
Habit: Shrub, tree, armed, generally spreading from underground parts. Leaf: odd-1-pinnate, alternate, deciduous; stipular spines generally not gland-dotted. Inflorescence: raceme, axillary. Flower: calyx bell-shaped, lobes 5; petals 5, white or pink, banner reflexed; 9 filaments fused, 1 free. Fruit: flat [or plump], not narrowed between seeds, dehiscent.
Etymology: (J. Robin (1550--1629), V. Robin (1579--1662), French botanists who introduced genus to Eur) Note: Robinia hispida L. spreading from planted plants in Sacramento River Delta, potentially naturalized.
eFlora Treatment Author: Matt Lavin, Duane Isely & Elizabeth McClintock
Reference: Lavin et al. 2003 Syst Bot 28:387--409
Unabridged Reference: Lavin & Sousa 1995 Syst Bot Monogr 45:117--124
Robinia pseudoacacia L.
Habit: Tree. Flower: corolla 1.5--2 cm. Chromosomes: 2n=20.
Ecology: Locally common near abandoned houses, roadsides, canyon slopes, streambanks; Elevation: 50--1900 m. Bioregional Distribution: CA-FP, GB; Distribution Outside California: native to eastern United States, widely cultivated. Toxicity: TOXIC: ingested seeds, leaves, bark may be fatal to humans, livestock. Flowering Time: May--Jun
Jepson eFlora Author: Matt Lavin, Duane Isely & Elizabeth McClintock
Reference: Lavin et al. 2003 Syst Bot 28:387--409
Index of California Plant Names (ICPN; linked via the Jepson Online Interchange)
View the CDFA Pest Rating page for Robinia pseudoacacia
Weed listed by Cal-IPC

Previous taxon: Robinia neomexicana
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Botanical illustration including Robinia pseudoacacia

botanical illustration including Robinia pseudoacacia

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Citation for this treatment: Matt Lavin, Duane Isely & Elizabeth McClintock 2012, Robinia pseudoacacia, in Jepson Flora Project (eds.) Jepson eFlora,, accessed on June 16, 2024.

Citation for the whole project: Jepson Flora Project (eds.) 2024, Jepson eFlora,, accessed on June 16, 2024.

Robinia pseudoacacia
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©2017 Julie Kierstead Nelson
Robinia pseudoacacia
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©2008 Keir Morse
Robinia pseudoacacia
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©2010 Steve Matson
Robinia pseudoacacia
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©2012 Steve Matson
Robinia pseudoacacia
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©2017 Julie Kierstead Nelson

More photos of Robinia pseudoacacia
in CalPhotos

Geographic subdivisions for Robinia pseudoacacia:
1. You can change the display of the base map layer control box in the upper right-hand corner.
2. County and Jepson Region polygons can be turned off and on using the check boxes.
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).