706 MISC. PUBLICATION 4 2 3, U. S. DEPT. OF AGRICULTURE 



4. CRESSA 



Plant small, perennial, herbaceous, silky- villous ; stems erect or 

 spreading, very leafy; leaves sessile, narrowly elliptic, entire; flowers 

 small, solitary in the upper axils, rather crowded; corolla whitish, the 

 lobes becoming reflexed. 



1. Cressa truxillensis H. B. K., Nov. Gen. et Sp. 3: 119. 1818. 



Along the Little Colorado River (Coconino County), near Phoenix 

 (Maricopa County), Gila Crossing (Pinal County), Yuma (Yuma 

 County), 100 to 4,000 feet, strongly saline soil, May to August. 

 Texas to southern Utah and southern California, south to tropical 

 America. 



5. JACQUEMONTIA 



Plants annual or perennial, often suffruticose, pubescent; leaves 

 petioled, the blades entire, rounded or subcordate at base; flowers 

 long-peduncled, solitary or in small loose inflorescences, the corolla 

 funnelform, blue or lavender; sepals all alike or the outer ones much 

 broader than the inner ones. 



Key to the species 



1. Plant annual (in Arizona) ; stems herbaceous throughout; herbage loosely soft- 

 pilose; sepals nearly alike in size and shape, lanceolate or lance-ovate, 

 acuminate; corolla narrowly funnelform, 8 to 10 mm. long, deep blue. 



1. J. PALMERI. 



1. Plant perennial; stems woody at least toward the base; herbage finely canescent 

 or subtomentose, the hairs mostly appressed; outer sepals much wider than 

 the inner ones, broadly ovate or suborbicular, acutish or apiculate; corolla 

 broadly funnelform, 20 to 25 mm. long, pale lavender 2. J. pringlei. 



1. Jacquemontia palmeri S. Wats., Amer. Acad. Arts and Sci. Proc. 



24: 63. 1889. 

 Canyons on the western slope of the Baboquivari Mountains (Pima 

 County), about 4,000 feet, September and October. Southern Ari- 

 zona, Sonora, and Baja California. 



2. Jacquemontia pringlei A. Gray, Amer. Acad. Aits and Sci. Proc. 



17: 227. 1882. 

 Santa Catalina Mountains (Pima County), also a doubtful record 

 from the Chiricahua Mountains, 3,000 to 4,000 feet, canyons, July to 

 September, type from the Santa Catalina Mountains (Pringle). 

 Southern Arizona to Central America. 



6. CONVOLVULUS. Bindweed 



Plants mostly perennial, herbaceous; stems (in the Arizona species) 

 twining or trailing; leaves more or less lobed; corolla broadly funnel- 

 form, white or pink; stigmas more or less elongate; capsule normally 

 2-celled or imperfectly 4-celled. 



C. tricolor L., a w annual with erect or spreading stems, narrow entire leaves, 

 and small but showy, parti-colored flowers, is sometimes cultivated as an orna- 

 mental. Specimens of what appears to be this species were collected at Tucson 

 by Tourney in 1892, but there is no evidence that the plant has become established 

 in Arizona. 



