Jepson Flora Project: Jepson Interchange    

link to manual TREATMENT FROM THE JEPSON MANUAL (1993) previous taxon | next taxon
Jepson Interchange (more information)
©Copyright 1993 by the Regents of the University of California
For up-to-date information about California vascular plants, visit the Jepson eFlora.



Duncan M. Porter

Herb, shrub, often armed; caudex present or not
Stem branched; nodes often angled, swollen
Leaves 1-compound, opposite; stipules persistent or deciduous; leaflets entire
Inflorescence: flowers 1–2 in axils
Flower bisexual; sepals 5, free, persistent or deciduous; petals 5, free, generally spreading, sometimes twisted and appearing propeller-like; stamens 10, sometimes appendaged on inside base; ovary superior, chambers 5–10, ovules 1–several per chamber, placentas axile
Fruit: capsule or splitting into 5–10 nutlets
Genera in family: 26 genera, ± 250 species: widespread especially in warm, dry regions; some cultivated (Guaiacum, lignum vitae; Peganum, harmal (NOXIOUS and illegal); Tribulus, caltrop (pernicious)). Peganum harmala L. has been reported as a pernicious weed near Daggett, San Bernardino Co
Reference: [Porter 1972 J Arnold Arbor 53:531–552]



Stem prostrate, spreading radially, < 1 m
Leaf even-1-pinnate; stipules ± leaf-like
Inflorescence: flowers solitary in axils
Flower: sepals deciduous; petals yellow, deciduous
Fruit 5-lobed, splitting into 5 nutlets, each with 2–4 stout spines; style deciduous; peduncle reflexed
Seeds 3–5 per chamber
Species in genus: ± 12 species: especially dry Africa
Etymology: (Greek: caltrop, weapon used to impede cavalry, from armed fruit)


T. terrestris L.

Stem ± silky or appressed-hairy, sharply bristly to glabrous
Leaf: stipules 1–5 mm; leaflets 6–12
Flower < 5 mm wide; peduncle < subtending leaf
Fruit 5 mm, < 1 cm wide, ± flat, hairy, gray or yellowish; spines 4–7 mm, spreading, hairy to glabrous
Ecology: Roadsides, railways, vacant lots, other dry, disturbed areas
Elevation: generally < 1000 m.
Bioregional distribution: California
Distribution outside California: to Wyoming, e US, c Mexico; native to Mediterranean
Flowering time: Apr–Oct
First collected in CA in 1902; long a pernicious weed, now controlled by introduced weevils. TOXIC to livestock in vegetative condition, fruits cause mechanical injury.

previous taxon | next taxon
bioregional map for TRIBULUS%20terrestris being generated
YOU CAN HELP US make sure that our distributional information is correct and current. If you know that a plant occurs in a wild, reproducing state in a Jepson bioregion NOT highlighted on the map, please contact us with that information. Please realize that we cannot incorporate range extensions without access to a voucher specimen, which should (ultimately) be deposited in an herbarium. You can send the pressed, dried collection (with complete locality information indicated) to us (e-mail us for details) or refer us to an accessioned herbarium specimen. Non-occurrence of a plant in an indicated area is difficult to document, but we will especially value your input on those types of possible errors (see automatic conversion of distribution data to maps).

Retrieve Jepson Interchange Index to Plant Names entry for Tribulus terrestris
Retrieve dichotomous key for Tribulus
Overlay Consortium of California Herbaria specimen data by county on this map
Show other taxa with the same California distribution | Read about bioregions | Get lists of plants in a bioregion
Return to the Jepson Interchange main page
Return to treatment index page
  • This page is no longer being maintained.

University & Jepson Herbaria Home Page |
General Information | University Herbarium | Jepson Herbarium |
Visiting the Herbaria | On-line Resources | Research |
Education | Related Sites
Copyright © by the Regents of the University of California