Taxonomy
- Kingdom: Plantae
- Clade: Tracheophytes → Angiosperms → Monocots → Commelinids
- Order: Poales
- Family: Poaceae (true grasses)
- Genus: Cenchrus
- Species: Cenchrus tribuloides (L.) Morrone
Synonyms
- Pennisetum tribuloides (L.) Schult. & Schult.f.
Common Names
- Tribuloid sandbur
- Rough sandbur
Description
Cenchrus tribuloides is an annual or short‑lived perennial grass forming low, tufted clumps. Stems (culms) are slender, erect to creeping, typically 10–50 cm tall. Leaves are linear, glabrous, and terminate in a short ligule. The inflorescence is a spikelet that matures into a hardened, spiny bur (called a “caryopsis” in Cenchrus) bearing several sharp, hooked awns. The burs are conspicuous, 5–15 mm long, and readily attach to animal fur, clothing, or machinery, facilitating zoochorous seed dispersal.
Phenology
Flowering generally occurs from late spring to early summer in the native range, with seed set following shortly thereafter.
Distribution and Habitat
- Native Range: Southern United States (e.g., Texas, Florida), Mexico, the Caribbean islands, Central America, and northern South America.
- Introduced Range: Reports exist of the species in tropical and subtropical regions outside its native area, often as a weed of disturbed sites.
The species prefers sandy, well‑drained soils and is commonly found in open, disturbed habitats such as coastal dunes, roadsides, fields, and pastures. It tolerates full sun and moderate drought conditions.
Ecology
The spiny burs are an adaptation for epizoochorous dispersal; they attach to mammals and humans, allowing seeds to be carried considerable distances. The plant can become locally abundant in disturbed habitats, sometimes outcompeting native vegetation.
Economic and Agricultural Significance
Cenchrus tribuloides is generally regarded as a minor weed in agricultural settings, particularly in pasture and crop fields where its burs can cause minor injuries to livestock and irritation to humans. There are no known major economic uses.
Conservation Status
The species has not been evaluated by the International Union for Conservation of Nature (IUCN); it is not considered threatened within its native range.
References
- USDA, Natural Resources Conservation Service. “PLANTS Database: Cenchrus tribuloides.”
- Royal Botanic Gardens, Kew. “Plants of the World Online: Cenchrus tribuloides.”
- Flora of North America Editorial Committee. “Cenchrus tribuloides.” Flora of North America eFloras.org.
All information presented reflects current, verifiable botanical sources.
