Guaiacum coulteri A. Gray

Guaiacum coulteri A. Gray, Mem. Am. Acad. II. 5 : 312. 1855
Guaiacum a/rum Sesse & Moc. Fl. Mex. 118. 1894. Not G. a/rum L. 1753.
Shrub 1-3 in. high; leaves 3-6 cm. long; leaflets 6-10, linear-oblong, 1-2.5 cm. long, 4-8 mm. wide, mucronate, glabrous, coriaceous, minutely veiny; petioles and rachis pubescent; stipules subulate; flowers axillary, 3-9 or more; pedicels 10-15 mm. long, slender, pubescent; sepals 5, 4-6 mm. long, unequal, broadly oblong or oblong-orbicular, rounded at the apex, minutely pubescent on the inner surface ; petals 5, blue, obovate, 9-15 mm. long, 5-7 mm. broad ; ovary 5-celled, narrowly obovate, compressed, glabrous ! style short, persisting; filaments filiform from a broad flat base; anthers 3 mm. long; fruit greenish, 5-carpellary or by abortion 2-4-carpellary, obcordate, 12-15 mm. long, 17 mm. broad, retuse, mucronulate, the carpels carinate on the back ; seed ellipsoid, 10-12 mm. long, 6-7 mm. wide, brown, covered with a pale-yellowish aril ; endosperm white, very thick, bony; cotyledons flat, very thin, bright-yellow, oblong or ellipsoid, 6 mm. long, 4 mm. broad.
Type locality : Hills between Rayon and Ures, Sonora. Distribution : Sonora, Sinaloa, Guerrero, Tepic, and Oaxaca.

Guaiacum coulteri is a species of flowering plant in the family Zygophyllaceae, that is native to western Mexico and Guatemala.