BUCKWHEAT FAMILY 5 



Involucres 3-5-toothed, if 6-toothed the tube not 6-ribbed. 

 Involucral tube 3-angled or 4-5-ribbed, not corrugated. 



Involucre 4— 5-ribbed and 4-S-toothed, one tooth much longer than the others, all tipped with straight 



spines. 25. C. spinosa. 



Involucre 3-angled, not ribbed. 



Involucral teeth uncinate, equal. 



Involucral teeth 3; bracts seldom foliaceous. 26. C. Orcuttiana. 



Involucral teeth 6, the 3 inner minute. 27. C. polygonoides. 



Involucral teeth 3, unequal, these and the bracts ending in long straight spines. 



28. C. rigida. 

 Involucral tube cylindric, corrugated but not ribbed. 



Involucral teeth S, one much larger than the other four, all recurved above; tube obscurely corru- 

 gated. 29. C. Watsonii. 

 Involucral teeth 3, all similar; tube conspicuously corrugated. 30. C. corrugata. 

 Bracts 3-lobed. 



Involucres not spurred at base; 4-toothed at apex. 

 Bracts minute; involucral teeth equal. 



Involucral teeth 4. 31. C. Vortriedei. 



Involucral teeth 5. 32. C. insignis. 



Bracts conspicuous; involucral teeth unequal. 



Bracts unilateral; involucre not 4-angled. 33. C. californica. 



Bracts orbicular-perfoliate; involucre 4-angled. 34. C. perfoliata. 



Involucres with 3-6 spurs at base, 5-6-toothed at apex. 



Spurs of the involucre 3, stout and nearly as broad as the tube; involucral teeth straight. 



35. C. Thurberi. 



Spurs of the involucre 6, slender and spine-like; involucral teeth uncinate. 36. C. leptoceras. 



1. Chorizanthe brevicornu Torr. 

 Brittle Chorizanthe or Spine-flower. Fig. 1305. 



Chorizanthe brevicornu Torr. Bot. Mex. Bound. 177. 1859. 



Erect annual herb, 1-2 dm. high, branches ascending, very fragile at the nodes when mature. 

 Leaves oblanceolate, 3-6 cm. long; bracts opposite, the lower bracts foliaceous, lanceolate to 

 oblanceolate, apiculate, the upper reduced ; involucres solitary in the axils of the branches of the 

 cymose inflorescence, cylindric, slightly curved, 4 mm. long, 6-toothed, the teeth short, nearly 

 equal, uncinate ; flowers short-pedicelled ; calyx 3-4 mm. long, glabrous, the tube slender, lobes 

 similar, linear-oblong, 1 mm. long ; stamens 3. 



Sandy desert plains and hills, Lower Sonoran Zone; Mono County, California, to northern Lower California, 

 southwestern Utah, and southern Arizona. Type locality: Gila River, Arizona. March-June. 



2. Chorizanthe spathulata Small. 

 Spatula-leaved Chorizanthe or Spine-flower. Fig. 1306. 



Chorizanthe spathulata Small ex Rydb. Bull. Torrey Club 39: 309. 1912. 



Erect annual, 10-15 cm. high, much branched from the base, somewhat canescent with an 

 appressed pubescence, very fragile at the nodes when mature. Leaves basal, 2-5 cm. long, the 

 blades broadly spatulate, rounded at apex, abruptly narrowed below to a winged petiole of equal 

 or greater length, tomentose beneath, green and scantily pubescent above ; lower bracts foliaceous, 

 oblanceolate, the upper reduced and acicular ; involucres 1-3 in the axils of the loose cyme, nar- 

 rowly cylindric, 4-5 mm. long, 6-ribbed and 6-toothed, the teeth slender, short, uncinate, recurved, 

 3 shorter than the alternating ones ; calyx and stamens as in C. brevicornu. 



Dry sandy or gravelly soils, Upper Sonoran Zone; southern Idaho, western Nevada, and adjacent (Mono 

 and Inyo Counties) California. Type locality: Big Butte Station, Idaho. June-July. 



3. Chorizanthe angustifolia Nutt. 

 Narrow-leaved Chorizanthe or Spine-flower. Fig. 1307. 



Chorizanthe angustifolia Nutt. Journ. Acad. Phila. II. 1: 167. 1848. 



Chorizanthe angustifolia var. Eastwoodiae Goodman, Ann. Mo. Bot. Gard. 21 : 42. 1934. 



Plants prostrate or decumbent, branches several from the base, 18-40 cm. long, canescent with 



appressed-villous pubescence. Leaves basal, oblanceolate to spatulate, long-petioled, 2-5 cm. long ; 



bracts opposite, the lower similar to the basal leaves, the uppermost much reduced and acicular, 



densely appressed-villous; involucres in scattered head-like cymes, about 3.5 mm. long, the tube 



cylindric, 3-angled, 6-toothed, the larger teeth about equaling the tube, divergent, straight except 



the uncinate tip; calyx scarcely exserted, 2-2.5 mm. long, the lobes oblong, acute to truncate, 



erose at summit ; stamens 9, rarely reduced to 3. 



Sandy soils mainly near the coast, Upper Sonoran Zone; Moro Bay, San Luis Obispo County, to San Diego, 

 California. Type locality : "Pueblo los Angeles." April-June. 



4. Chorizanthe procumbens Nutt. 

 Prostrate Chorizanthe or Spine-flower. Fig. 1308. 



Chorizanthe procumbens Nutt. Journ. Acad. Phila. II. 1: 167. 1848. 



Chorizanthe uncinata Nutt. Journ. Acad. Phila. II. 1: 167. 1848. 



Chorizanthe procumbens var. albiflora Goodman, Ann. Mo. Bot. Gard. 21: 87. 1934. 



Stems branching from the base, and procumbent or ascending, 3-15 cm. long, strigose-tomen- 

 tulose. Leaves oblanceolate, 2-7 cm. long, slender-petioled, woolly-tomentose, glabrate above; 



