Burke: Cenchrus spinifex vs. Cenchrus longispinus

	Cenchrus spinifex	Cenchrus longispinus
		longspine sandbur, mat sandbur
Habit		Prostrate, widely matted annual, the culms solid.
Leaves		Sheaths open, keeled, glabrous; ligules 1-1.5 mm. long with a fringe of hairs 2-4 times as long as the basal membrane; blades flat or folded, 2-6 mm. broad.
Flowers		Inflorescence a crowded raceme of 5-10 spiny burs; spikelets 2-flowered, usually 2 per bur, 5-6 mm. long, tightly enclosed within and deciduous with the burs; lower flower sterile, upper flower perfect; burs finely pubescent, the spines numerous, flattened, 4-6 mm. in diameter; glumes narrow, shorter than the lemmas.

	Cenchrus spinifex	Cenchrus longispinus
Flowering time		July-September
Habitat		Sandy river banks and other disturbed, seasonally moist areas.
Distribution	[WildflowerSearch map]	Occurring chiefly east of the Cascades crest in Washington; British Columbia to Mexico, east to the Atlantic Coast. [WildflowerSearch map] [BONAP county map]
Origin		Introduced
Conservation status	Not of concern	Not of concern
Sibling taxa	C. longispinus
Web links	Local floras: CA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local floras: BC, CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Cenchrus longispinus

longspine sandbur, mat sandbur

Habit

Prostrate, widely matted annual, the culms solid.

Leaves

Sheaths open, keeled, glabrous;

ligules 1-1.5 mm. long with a fringe of hairs 2-4 times as long as the basal membrane;

blades flat or folded, 2-6 mm. broad.

Flowers

Inflorescence a crowded raceme of 5-10 spiny burs;

spikelets 2-flowered, usually 2 per bur, 5-6 mm. long, tightly enclosed within and deciduous with the burs; lower flower sterile, upper flower perfect; burs finely pubescent, the spines numerous, flattened, 4-6 mm. in diameter;

glumes narrow, shorter than the lemmas.