STANDLEY — TREES AND SHRUBS OF MEXICO 1509 



Suffrutescent below, up to 2.5 meters high; stem denselj^ and harshly griseous- 

 puberulous; leaves chieflj' ovate, petioled, the blades 4 to 11 cm. long, 1.5 to 5 

 cm. wide, serrate, verj' harsh above, puberulous beneath; heads very numerous, 

 about 4 mm. high. "Hierba del carbonero" (Valley of Mexico). 



A decoction of the flowers is reported to be used as a remedy for catarrh, 

 5a. Archibaccharis mucronata paniculata (Donn. Smith) Blake. 



Diplostephium paniculatum Donn. Smith, Bot. Gaz. 23: 8. 1897. 



Hemibaccharis mucronata -paniculata Blake, Contr. U. S. Nat. Herb. 20: 551. 

 1924. 



Veracruz to Oaxaca and Chiapas. Guatemala; type collected between San 

 Martin and Todos Santos, Guatemala. 



Pubescence soft; lower leaf surface and often the stem densely tomentose. 



6. Archibaccharis sescenticeps Blake. 



Hemibaccharis sescenticeps Blake, Contr. U. S. Nat. Herb. 20: 552. 1924. 



Jalisco to Mexico and Guerrero; type from Mount Ixtaccihuatl, State of 

 Mexico. 



Suffrutescent (?), stout, glabrous and glaucescent below or thinly arachnoid; 

 leaves petioled, the blades 6 to 13 cm. long, 3 to 6 cm. wide, serrate, short- 

 acuminate, smoothish above; heads 3.5 to 4.5 mm. high. 



7. Archibaccharis androgyna (T. S. Brandeg.) Blake. 



Baccharis androgyna T. S. Brandeg. Univ. Calif. Publ. Bot. 6: 77. 1914. 



Hemibaccharis androgyna Blake, Contr. U. S. Nat. Herb. 20: 552. 1924. 



Known only from the type locality, Cerro de Boqueron, Chiapas. 



Slender, suffrutescent, glabrous throughout; leaves on short but slender petioles, 

 the blades narrowly lanceolate, 5.5 to 9.5 cm. long, 1 to 1.8 cm. wide, falcate- 

 attenuate, serrulate; panicles many-headed, ternainal, 5 to 8 cm. wide; pistillate 

 heads 3 to 4 mm. high. 



8. Archibaccharis asperifolia (Benth.) Blake. 

 Baccharis asperifolia Benth. PI. Hartw. 86. 1841. 



Conyza asperifolia Benth. & Hook.; Hemsl. Biol. Centr. Amer. Bot. 2: 126. 1881. 



Baccharis scabridula T. S. Brandeg. Univ. Calif. Publ. Bot. 6: 77. 1914. 



Hemibaccharis asperifolia Blake, Contr. U. S. Nat. Herb. 20: 552. 1924. 



Mexico to Chiapas. Guatemala to Nicaragua; type from Mixco, Guatemala. 



Suffrutescent below, uij to 3 meters high, essentially glabrous and usually 

 glaucescent below; leaves chiefly elliptic, 4 to 11 cm. long, 1 to 3.5 cm. wide, 

 acuminate, subentire or serrate; panicles large, with innumerable heads, these 

 2.5 to 5 mm. high. 



DOUBTFUL SPECIES. 



Baccharis elegans seemannii Schultz Bip. in Seem. Bot. Voy. Herald 303. 

 1856. This variety, described from the Sierra Madre, may belong in this genus. 

 The description Is very brief, and no specimens have been examined bj' the 

 writer. 



31. PLXJCHEA Cass. Bull. Soc. Philom. Paris 1817: 31. 1817. 

 Shrubby or herbaceous; leaves alternate, entire or toothed; heads disciform, 

 medium-sized, cymose or cymose-panicled, purplish or whitish; involucre several- 

 seriate, of dry, often purplish phyllaries; outer flowers pistillate, several-seriate, 

 with filiform corollas; inner flowers hermaphrodite; anthers sagittate at base, with 

 caudate auricles; achenes small, 4 or 5-angled; pappus 1-seriate, setose. 



Stem winged by the decurrent leaf bases 1. P. adnata. 



Stem wingless. 



Leaves narrowly elliptic, silky-pubescent, sessile, 5 cm. long or less. 



2. P. sericea. 



Leaves broadly elliptic or oval, not silky-pubescent, petioled,. 10 cm. long or 



more 3. P. odorata. 



