STANDLEY TREES AND SHRUBS OF MEXICO. 811 



Lower surface of leaves stellate-tomentose, the hairs loose and spreading. 



Sepals 5 to 7 mm. long 11. a. berlandieri. 



Sepals 2.5 to 3 mm. long. 



Upper leaves long-petiolate ; leaves conspicuously cordate at base. 



10. A. magna. 

 Upper leaves nearly sessile; leaves rounded or subcordate at base. 



Sepals green 12. A. palmeri. 



Sepals brown-purple 13. A. jaliscana. 



1. Ayenia ovata Hemsl. Diag. PI. Mex. 4. 1878. 



Ayenia mollis T. S. Brandeg. Univ. Calif. Publ. Bot. 3: 385. 1909. 



Hidalgo and Puebla ; type from Zimapan, Hidalgo. 



Shrub ; leaves slender-petiolate, broadly ovate, acute, cordate at base, den- 

 tate, densely tomentose, 2.5 to 5 cm. long; flowers solitary or in pedunculate 

 umbels, long-pedicellate ; fruit about 1 cm. in diameter, covered with very 

 long filiform hairy appendages. 



2. Ayenia manzanilloana Rose, Contr. U. S. Nat. Herb. 1: 309. 1895. 

 Known only from the type locality, Manzanillo, Colima. 



Leaves short-petiolate, 2 to 5 cm. long, long-acuminate, rounded at base, 

 serrate, green, glabrate ; fruit 5 mm. in diameter, glabrate, covered with 

 brown glands. 



3. Ayenia wrightii Robinson, Bot. Gaz. 16: 340. 1891. 

 Ayenia compacta Ro.se, Contr, U. S. Nat. Herb. 8:321. 1905. 



Ayenia peninsularis T. S. Brandeg. Univ. Calif. Publ. Bot. 6: 368. 1917. 



Baja California and Sinaloa ; type from head of Mazatlan River, Sinaloa. 



Plants 30 to 60 cm. high, suffrutescent, slender, the branches pubescent ; 

 leaves slender-petiolate, 1 to 5 cm. long, acute or obtuse, finely pubescent or 

 glabrate, serrate-dentate; fruit about 5 mm. in diameter. 



4. Ayenia rotundifolia Hemsl. Diag. PI. Mex. 4. 1878. 

 Known only from the type locality, Zimapan, Hidalgo. 



Leaves slender-petiolate, ovate-rounded, 1 to 2.5 cm. wide, obtuse or retuse, 

 sometimes cordate at base, crenate-dentate, soft-pubescent ; sepals about 4 mm. 

 long. 



5. Ayenia pusilla L. Syst. Nat. ed. 10. 1247. 1759. 

 Ayenia filiformis S. Wats. Proc. Amer. Acad. 24: 42. 1889. 

 Ayenia dcntata T. S. Brandeg. Univ. Calif. Publ. Bot. 6: 56. 1914. 



'i Ayenia reflexa T. S. Brandeg. Univ. Calif. Publ. Bot. 6: 369. 1917. 



Ayenia cuneata T. S. Brandeg. Univ. Calif. Publ. Bot. 6: 369. 1917. 



Nearly throughout Mexico. Widely distributed in the warmer parts of the 

 Western Hemisphere. 



Plants slender, essentially annual but often becoming suffrutescent; leaves 

 very variable in form, lanceolate to suboricular, 1 to 5 cm. long, rounded to 

 acuminate at apex, obtuse to cordate at base, dentate, pubescent or glabrous; 

 fruit 5 to 6 mm. in diameter, pubescent or glabrate, covered with long or short 

 spinelike processes. 



The Mexican plants exhibit great variation in the shape and pubescence of 

 the leaves, but the West Indian specimens are rather uniform. None of the 

 segregates which have been described seem clearly differentiated from the 

 mass of material from the West Indies and the southern United States gen- 

 erally referred to A. pusilla, and it has not appeared practicable to recognize 

 any of them. The glands of the petals are so variable in size and form that 

 they do not furnish a satisfactory basis for specific segregation. 



