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FNA | Family List | FNA Vol. 5 | Polygonaceae | Chorizanthe

19. Chorizanthe uniaristata Torrey & A. Gray, Proc. Amer. Acad. Arts. 8: 195. 1870.

One-awn spineflower

Plants spreading or ascending, 0.2-0.6(-0.8) × 0.5-4(-5) dm, appressed-pubescent. Leaves basal; petiole 0.5-2 cm; blade oblanceolate, 0.5-1.5(-2) × 0.2-0.8 cm, thinly pubescent. Inflorescences with involucres in small open clusters 0.5-1.5 cm diam., greenish to grayish or reddish; bracts 2, sessile, usually leaflike, oblanceolate to elliptic, 0.5-1.5 cm × 1.5-5 mm, gradually reduced and becoming scalelike at distal nodes, linear, aciculate, acerose, 0.4-1.2 cm × 1-2(-3) mm, awns straight, 1.5-4 mm. Involucres 3-10, grayish to reddish, urceolate, slightly ventricose basally, 2-3 mm, without scarious or membranous margins, slightly corrugate, densely grayish-pubescent; teeth widely spreading to divergent, unequal, 0.3-0.5 or 3-6 mm; awns straight or uncinate, unequal, with longer anterior one straight, 2.5-5.5 mm, others spreading, uncinate, 0.3-0.5 mm. Flowers included or only slightly exserted; perianth bicolored with floral tube greenish white and tepals white, cylindric, 2-3 mm, sparsely pubescent; tepals connate 3 their length, dimorphic, linear-oblong, those of outer whorl spreading, narrowly oblong, 1.5 times longer than those of inner whorl, rounded but with minute cusp or 3 teeth apically, those of inner whorl erect to slightly spreading, acute, entire apically; stamens 3, included; filaments distinct, 1-2 mm, glabrous; anthers white, ovate, 0.4-0.5 mm. Achenes brown, globose-lenticular, 2-3 mm. 2n = (78), 80, (82).

Flowering Apr-Jul. Sandy to gravelly talus or clay flats and slopes, mixed grassland and chaparral communities, pine-oak woodlands; 800-1900 m; Calif.

Chorizanthe uniaristata is scattered in the Inner Coast Ranges and across the Transverse and Tehachapi ranges to the southern Sierra Nevada.

One-awn spineflower is a polyploid, but whether an autopolyploid or an autoallopolyploid has not been determined. It has the smallest meiotic chromosomes observed by C. B. Hardham (1989).


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