74 PROCEEDINGS OF THE AMERICAN ACADEMY. 
branches: leaves linear, the largest 3 cm. long, acuminate, sometimes 
mucronate, scabrous, with 2 to 4 pairs of sete toward the bases: heads in 
an open leafy cyme, or glomerate: involucre 5 mm. high, about 12-flow- 
ered; the 5 linear acuminate bracts strongly conduplicate and slightly 
keeled toward the bases: rays narrow, 2 mm. long: pappus of subequal 
slender awns, 3} to 5 mm. long; in the disk 5 or 6 (rarely 7), in the ray 
2 or 3: akenes 2} to 3} mm. long, minutely short-setose or glabrate. — 
Prodr. v. 100; Gray, Proc. Am. Acad. xix. 46. — Eastern Mexico, near 
the coast. Tamauxipas, San Fernando (Berlandier, nos. 1537, 3037), 
near Tampico (Palmer, 1879, no. 1096); Vera Cruz, between Tanto- 
yuca and Tampico (Berlandier, no. 732), near Tantoyuca (Berlandier, 
no. 2152). ae 
* x * Erect, simple or branching mostly above the base, stems purplish: leaves 
linear or lanceolate, the glands scattered or in lines between midrib and veil 
gins: heads scattered or solitary on long slender peduncles (2 or more times 
as long as the head): involucral bracts about 5, acute or acuminate, purplish : 
rays yellow or purplish. (Forms of P. diffusa may be looked for here.) 
+ Awns obviously dilated at the base. 
ré P. capillaris, DC. Erect smooth or minutely pubescent annuals, 1 
or 2 dm. high, with slender subtetragonous stems diffusely branching above: 
leaves linear, mucronate, the larger 3 cm. long, 3 mm. wide, above scabridu- 
lous, beneath with prominent midribs and two rows of large glands about 
midway between the margins and midribs; margins with 2 to 5 pairs 0 
setze below the middle: peduncles many, terminal and from the upper 
axils, capillary, 2 or 3 cm. long, 2—4-bracteate: involucres 4 to 6 mm. high, 
10-15-flowered: rays oblong, 2 mm. long: pappus 2 to 6 (or even 1) 
slender awns 4 or 5 mm. long, with or without a few squamelle at the 
bases: akenes hardly equalling the pappus, appressed short-setose OF 
glabrate. — Prodr. v. 99. P. Jaliseana (printed Taliscana), Hook. & 
Arn. Bot. Beech. Voy. 296 ; Hemsley, Biol. Centr.— Am. Bot. ii. 225, 12 
part; Gray, Proc. Am. Acad. xix. 46; Klatt, Leopoldina, xx. 91 
(reprint 4).— Southwestern Mexico. JALisco, Jalisco (Beechy fide 
Hook. & Arn.), Rio Blanco (Palmer, 1886, no. 760), Plains of Guadala- 
jara (Pringle, no.1813, in part); Oaxaca, near Las Bacas, fide DC. l c. 
There is little doubt that P. Jaliscana, described from incomplete material, 
is the same as De Candolle’s plant. P. Jaliscana was based upon a form 
with squamelle at the base of the awns, but in Palmer’s Rio Blanco plants — 
akenes with and without squamelle are found on the same individual. 
Var. paucicapitata. Slender, with a few elongated ascending F 
branches: leaves variable in size, the largest 5 cm. long, 5 mm. wide, 
Soo ere 
