Tribulus terrestris L.   Zygophyllaceae (Caltrop Family)   Old World Puncture Vine  Goat's Head

                                            July Photo

Plant Characteristics:  Annual, trailing, pubescent, often prostrate, branched from base, the stems 2-10 dm. long; lfts. 4-7 pairs, oblong or elliptic, 5-12 mm. long, stipules 11-5 mm.; fls. solitary, axillary, (4-) or 5 merous; petals yellow, obovate, 3-4 mm. long; fils. 10 (8), slender without appendages; carpels as many as petals, crested and armed with 2-4 spreading gray or yellowish spines 4-6 mm. long.

Habitat:  Naturalized in waste places, along roadsides, etc. through much of Calif. below 5000 ft., even on the deserts; to Atlantic Coast.  April-Oct.

Name:  Latin name of caltrop, the shape of which is suggested by the 3-pronged fruit.  (Munz, Flora So. Calif. 862).  Also, Greek, caltrop, a weapon used to impede cavalry.  (Hickman, Ed. 1099; Tribulus is Latin for "three pointed."  (Dale 200).  Latin, terrestris, of or belonging to the earth.  (Jaeger 260).  The species name may refer to the prostrate habit of the plant.  (my comment).

General:  Rare in the study area, having been found only once and this about 100 yards from Jamboree Rd. on the horse path built through Santa Heights in 1987.  (my comment).      The five nutlets equipped with 2-4 spreading spines fall apart at maturity pointing one spine upward to be disseminated by animals, shoes or rubber tires.  Within the bur, the seeds lay one above the other, separated by hard, horny tissue.  The largest germinates first and if there is only enough moisture for one, the others remain dormant until a more favorable time.  (Dale 200).      The root system of puncture vine consists of a simple tap root branching into a network of very fine rootlets, which so surround the soil particles as to take utmost advantage of the soil moisture.  This root habit enables the puncture vine to live under conditions of drought survived by few other plants.  The petals are usually open only in the morning, closing shortly after noon, except in cloudy weather.  Mechanical injuries to animals are frequent.  Cattle, horses, sheep, swine and dogs have all been known to receive wounds from puncture vine burs.  Mouth injuries are occasionally noted, but not so frequently as might be presumed from the prevalence of the seed in certain sections.  (Robbins, et al. 288,289).      Tribulus terrestris has been found to accumulate free nitrates in quantities capable of causing death or distress in cattle.  (Fuller 384).       Long a pernicious weed, now controlled by introduced weevils.  Toxic to livestock in vegetative condition.  (Hickman, Ed. 1099).       Some rather extensive studies have shown that the seeds and to a lesser degree, the foliage is a useful early treatment for elevated blood fats, including cholesterols.  It helps prevent the severity of arteriosclerosis and atherosclerosis.  The reasonable dose is one-half to one teaspoon of the powdered plant in hot water for tea, morning and early evening.  Puncture Vine is also useful in mild essential hypertension.  (Moore, Medicinal Plants of the Desert and Canyon West 96).         An extract of this common weed is gaining attention as a therapy for low libido and sexual dysfunction.  This herb, which has been used for centuries in India and Eastern Europe, has been shown to increase testosterone levels in men and women.  The plant has other benefits as well. It improves energy and mood and has been used by body builders for its ability to improve muscle strength.  A less expected benefit is improvement of cholesterol levels.  (Holt. S. The Sexual Revolution. San Diego: Promotion Publishing 1999.  An excerpt printed in Health and Healing, by  Dr. Julian Whitaker. July 2002 Vol. 12, No. 7  p.5).

Text Ref:  Dale 200; Hickman, Ed. 1099; Munz, Flora So. Calif. 862.

Photo Ref:  July-Aug 87 # 5,6.

Identity: by R. De Ruff.

Computer Ref:  Plant Data 340.

Have Plant Specimen.

Last edit 7/18/03.

                                                July Photo