Species Detail Forb

Flower Willow Lake - Sue Smith		Yavapai County Native & Naturalized Plants Tribulus terrestris - puncturevine Other Common Names: goat's head, puncture-weed, ground bur-nut, tackweed, torrito, bull-head Plant Form: Forb or Subshrub Family: Zygophyllaceae
Flower Willow Lake - Sue Smith


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Flowers Granite Mtn - Tr 308 Sue Smith	Leaves Willow Lake Sue Smith	Plant - summer Granite Mtn - Tr 308 Sue Smith	Plant - summer Willow Lake Sue Smith	Burs Granite Mtn - Tr 308 Sue Smith

Forb Plant Description

Origin: Introduced Life Cycle: Annual
General Desc: Prostrate plant trails up to 2-1/2 feet long, branched from the base and hairy. Spines of fruit are sharp enough to puncture bicycle tires and are painful to bare feet. Can also become embedded in fur and fabric.
Identification notes: Mat-forming annual with diffused, branching stems; leaves opposite, with 3 to 9 pairs of elliptic or oblong leaflets; flowers solitary in axils of leaves, flowers of 5 sepals and 5 pale yellow petals; flowers produce spiny nutlets.
Height: 2 inches

Habitat

Habitat Description: Cultivated areas, along roads, disturbed sites.
Plant Communities: Disturbed Areas
Elevation: Below 7000 feet

Flower Characteristics

Color: Yellow Shape: Regular not in clusters Tubular: N Flowering Period: Mar - Oct
Description: Solitary flowers in axils of smaller or abortive leaves, stems shorter than the subtending leaf; 5 sepals and 5 pale yellow petals .

Leaf and Stem Characteristics

Leaf Color: Dark green Leaf Type: Compound Leaf Shape: Round or oval Leaf Margin: Toothed Leaf Attachment: Opposite Leaves Clasp: N
Hairs: Leaves and stems Spines: N
Leaf Description: Leaf is pinnately compound to 2 inches long with leaflets to 1/2 inch long, lowest pair of leaflets unequal in size.

Fruit and Seed Characteristics

Fruit Color: Brownish-gray
Fruit Type: Capsule
Fruit Notes: Capsules break into 5 spiny nutlets, each with 2 larger spines; after separation the vicious tacklike nutlets land with larger spines upward. Two-spined segment resembles a goat's head with horns.
Seed Notes: Nutlets or "seeds" are hard and have a pair of 1/4 inch long sharp spines.


	Arizona Cooperative Extension Yavapai County 840 Rodeo Dr #C Prescott, AZ 86305 (928) 445-6590	Version 8.0 http://cales.arizona.edu/yavapaiplants/SpeciesDetailForb.php Last Updated: Dec 13, 2022 Content Questions/Comments: Email Matt Halldorson Legal Disclaimer