STANDLEY TEEES AND SHEUBS OF MEXICO 1507 



27. Eaccharis trinervis (Lam.) Pers. Syn. PI. 2: 423. 1807. 



'Wonyza trinervia Mill. Gard. Diet. ed. 8. Conyza no. 12. 1768. 



Conyza trinervis Lam. Encj'cl. 2: 85. 1786. 



Veracruz. Central and South America; type from Brazil. 



Shrubby, about 4 meters high, subscandent, the stem striate-angled, glabrous; 

 leaves ellii:)tic or oblong-elliptic to lance-elliptic or ovate-elliptic, the larger 5 to 

 9.5 cm. long, 1.5 to 3.5 cm. wide, entire, acute or acumina,te, strongl}' triplinerved; 

 panicles terminating stem and branches, rounded or narrow, many-headed; 

 involucre about 4 mm. high; achenes 5-nerved, sparsely hispidulous; pappus 

 brownish-tinged, 4 mm. long. " Canutillo,"' "hierba de Santo Domingo" 

 (El Salvador). 



27a. Baccharis trinervis rhesioides (H. B. K.) Baker in Mart. Fl Bras. 6^: 

 73. 1882. 



Baccharis rhexioides H. B. K. Nov. Gen. & Sp. 4; 66. 1820. 



Baccharis trichoclada DC. Prodr. 5: 400. 1836. 



San Luis Potosi and Tepic to Tabasco and Chiapas. Central and South 

 America; type from Montdn, Peru. 



Stem and sometimes veins of lower leaf surface more or less densely sordid- 

 tomentulose or puberulous; otherwise as in the typical form. "Barba fina" 

 (Guatemala); "tapabarranco" (El Salvador); "Santo Domingo" (Costa Rica); 

 "huichfn prieto" (San Luis Potosi, Seler). 



DOUBTFUL SPECIES. 



Bacch.\ris asperula Schauer, Linnaea 19: 725. 1S47. Said to be allied to 

 B. xalapensis H. B. K.; the type is Aschenhorn 464, from Zimapiln, Hidalgo. 



Baccharis LiNiFOLiA DC. Prodr. 5: 420. 1836. Based on specimens collected 

 by Haenke at Real del Monte, Hidalgo. 



Baccharis polygalaefolia H. B. K. Nov. Gen. & Sp. 4: 49. 1820. Based 

 on specimens collected at Mordn, Mexico, and in the Andes of Popayan, 

 Colombia. 



Baccharis spathulata Schauer, Linnaea 19: 724. 1847. Collected in Mexico, 

 without definite locality, by Aschenborn (no. 107). Said to be near B. poly- 

 galaefolia H. B. K. 



Baccharis trichotoma Klatt, Leopoldina 20: 91. 1884. Based on material 

 collected in Mexico by Liebmann. 



30. ARCHIE AC CHARIS Heering, Jahrb. Hamb. Wiss. Anst. 21: Beih. 3: 



40. 1904. 

 Reference: Blake, Hemibaccharis, a new genus of Baccharidinae, Contr. 

 U. S. Nat. Herb. 20: 543-554. pi- 48-61. 1924. 



Characters of Baccharis, but plants polygamo-dioecious; staminate plants as 



in Baccharis; pistillate heads with 1 to 15 central hermaphrodite sterile flowers. 



Leaves amplexicaul; heads larger, the pistillate 10 mm. high, the staminate 5 



to 8 mm. high. 



Stem densely pubescent with spreading gland-tipped hairs. .-1. A. oaxacana. 



Stem not glandular-pubescent 2. A. pringlei. 



Leaves not amplexicaul; heads smaller, not over 5.5 mm. high. 



Plants scandent or subscandent, the branches usually conspicuously zigzag; 

 heads in usually small rounded panicles terminating the numerous wide- 

 spreading branchlets. 

 Heads tiny, 2 to 3.5 mm. high; leaves chiefly ovate or elliptic. 



3. A. hirtella. 

 Heads 4 to 5.5 mm. high; leaves chiefly oval or oval-ovate _-4. A. torquis. 



