LEAVES: linear to broadly oblanceolate, usually broadest above the middle, commonly 1-2 cm long, narrowed gradually at base and abruptly at apex, sharp with terminal hair.

FLOWERS: in diffuse, lax, many-flowered inflorescence, on terminal and lateral branches with reduced leaves.

COROLLAS: white, not pilose, cleft usually more than halfway, the lobes spreading, not sharply reflexed, the throat flaring to nearly rotate.

FRUIT: hairs arising from tubercles, sometimes much reduced. 2n = 22, 66.

NOTES: See also parent taxon for further description. Along streams and in moist places in mixed forests; Apache, Cochise, Coconino, Gila; Graham, Greenlee, Navajo, Pima, Pinal, Santa Cruz cos.; 1200-2900 m (4000-9500 ft); Jun-Oct; CO, NM; Chih., Dgo., Son., Mex. Although easily distinguished in CO and NM, subsp. asperrimum in s AZ intergrades with subsp. mexicanum of Mex. and C. Amer. (Dempster, Madrofio 23:378-386. 1976).

REFERENCES: Dempster, Lauramay T. 1995. Rubiaceae. J. Ariz. - Nev. Sci. 29(l): 29.