STANDLEY TREES AND SHRUBS OF MEXICO 1569 



SuflFruticose; branches nearly glabrous; leaves short-petioled, lance-ovate, 

 acuminate, serrulate, sparsely strigose above, appressed-villous beneath; pe- 

 duncles monocephalous; involucre 2-seriate, the outer phyllaries foKaceous, 

 etrigose; achenes slender, 5 to 7 mm. long. (Description compiled.) 



23. Zexmenia scandens Hemsl. Biol. Centr. Amer. Bot. 2: 174. 1881. 

 Zexmenia trachylepis Hemsl. Biol. Centr. Amer. Bot. 2: 175. 1881. 

 Zexmenia dulcis Coulter, Bot. Gaz. 16: 99. 1891. 



Verhesina sylvicola T. S. Brandeg. Univ. Calif. Publ. Bot. 10: 419. 1924. 



Veracruz and Tabasco to Chiapas; type from Valley of C6rdoba, Veracruz. 

 Guatemala. 



Shrub, scandent or subscandent; branches sordidly tomentose-pilose or hispid- 

 pilose; petioles 5 to 15 mm. long; blades ovate or oblong-ovate, 7.5 to 11.5 cm. 

 long, 3 to 5 cm. wide, acuminate or acute, rounded or cuneate-rounded at base, 

 serrate, rough above, sordidly hirsute-pilose or hispid beneath; heads usually 

 numerous and cymose-panicled, sometimes in cymes of 1 to 3, medium-sized, 

 the pedicels usually 1 to 5 cm. long; involucre 5 to 7 mm. high, subequal or 

 graduate, the phyllaries mostly ovate to oblong or oval, obtuse or sometimes 

 acute, with short, often spreading, subherbaceous tips; achenes winged, 



24. Zexmenia leucactis Blake, Journ. Bot. Brit. & For. 53: 307. 1915. 

 Zexmenia chiapensis T. S. Brandeg. Univ. Calif. Publ. Bot. 6: 197. 1915. 

 Chiapas. Guatemala; type from Retahuleu. 



Shrub about 2.5 meters high; branches densely sordid-pilose, glabrate; petioles 

 7 to 15 mm. long; blades ovate or oblong-ovate, 6 to 11 cm. long, 2.8 to 4 cm. 

 wide, acuminate, cuneate or rounded at base, serrate, harsh above, densely and 

 softly griseous-pilosulous beneath; heads medium-sized, few, loosely cymose, the 

 pedicels sordid-pilose, 1 to 4 cm. long; rays yellow; involucre about 3-seriate, 

 obgraduate, the outermost phyllaries with ovate base and much narrower and 

 longer, loosely spreading, acuminate, herbaceous tips, the innermost much 

 shorter, unappendaged; achenes winged. 



DOUBTFUL SPECIES. 

 Zexmenia imbricata Schultz Bip. in Seem. Bot. Voy. Herald 306. 1856. 



Mexico, without definite locality. 



Suffruticulose, canescent, the stem glabrescent; petioles 1.6 cm. long; blades 

 triangular-ovate, 10 cm. long, 5 cm. wide and more, acute, subcordate at base, 

 dentate, scabrous; heads in the upper axils, about equaling the pedicels; involucre 

 6 mm. high, graduate, the phyllaries ovate-linear, obtuse, scabrous; achenes 

 winged. (Description compiled.) 

 Zexmenia lindenii Schultz Bip. in Seem. Bot. Voy. Herald 306. 1856. 



Lasianthaea lindenii Schultz Bip. in Seem. Bot. Voy. Herald 306. 1856, as 

 synonym. 



Known only from the type locality, Mirador, Veracruz. 



Leaves alternate, elliptic-lanceolate, 9 cm. long, 1.8 to 2.5 cm. wide, attenuate 

 at each end, petioled, serrate, featherveined, harsh above, tomentose beneath; 

 heads numerous. (Description compiled.) 



Perhaps a species of Verhesina. 

 Zexmenia macrocephala (Hook. & Arn.) Hemsl. Biol. Centr. Amer. Bot. 

 2: 173. 1881. 



Lipochaeta macrocephala Hook. & Arn. Bot. Beechey Voy. 436. 1840-41. 



Closely allied to Z. ghiesbreghtii A. Gray, and perhaps identical; type from 

 Tepic. 

 Zexmenia monocephala (DC.) Heynh. Nomencl. 2: 772. 1846. 



Lipochaeta monocephala DC. Prodr. 5: 610. 1836. 



Mexico, without definite locahty (type); Veracruz (according to W. W. Jones). 



