- Tribulus terrestris
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Plants are pubescent with weak, often prostrate stems. The stems are
pubescent, 20-100 cm long, radiating from a central crown and sometimes
branching from the same leaf axils as the flowers, forming mats many meters
wide. The leaves are pubescent, 2-6 cm long, short petioled, even-pinnately
compound. The leaves are opposite and one of each pair is distinctly larger
than the other, the larger with 12-18 leaflets, the smaller with 8-10.
The leaflets are opposite, oblong, 5-15 mm long, 2-5 mm wide, pubescent
on the lower surface and the midrib of the upper surface. Flowers are
8-10 mm wide, solitary from the axils of the small leaves, peduncles 2-15
mm long. The petals are yellow. The body of the fruit is ca. 1 cm thick,
splitting at maturity into 5 segments each of which has a line of horny
processes down the back and 2 lateral spines toward the center.
The species are annual or perennial and, due to the branching, prostrate
growth form, can cover a very large area of the substrate. The species
occur in many states, growing in sandy soils along railways and roadways,
backyards and waste places, and in some areas, along dune beaches.
Native plants are essentially excluded from places where puncturevines
grow. The spines on the fruits may cause mechanical injuries to animals
feeding on hay containing the fruit. A photosensitizing agent in the plant
causes poisoning in sheep when they eat flowering plants. The spiny fruits
are a problem in the areas in which they grow; in parking lots, they cause
punctures in rubber tires of bicycles and automobiles.
Links to more information
Website, video, and graphics by Rob Nelson
For more information on this plant or management please contact US Army Corp of Engineers