22 Contributions from the Gray Herbarium 
longa. Alae ellipticae apice obtusae vel rotundatae basi late cune- 
atae ad costam sparse puberulae 5.5-7 mm. longae 4 mm. latae. 
Petala superiora obovata infra ciliata ad 3.8 mm. longa. Carina 
glabra 4.5-4.8 mm. longa. Capsula deltoideo-ovata sursum mani- 
feste angustata basi truncato-rotundata ciliata et in lateribus pu- 
berula pilis brevibus patentibus emarginata 5.5—-7 mm. longa 5-6 
mm. lata. Semina cuneato-obovoidea breviter pilosa rugulosa 4 
mm. longa 2.6 mm. lata. Arillus capitelliformis minutus ad 0.5 mm. 
altus pilosus margine scarioso obsoleto. — GUERRERO: Acapulco, 
ct. 1894—Mar. 1895, Palmer 168 (TYPE COLL.: Ted. 
Fic. 10.— Very distinct in capsule and seed. Distributed as P. 
americana Mi 
Series @. Ohevazad; ser. nov.! Folia saepissime biformia, in- 
feriora saepissime ovalia ad oblongo-ovalia superiora saepissime 
longiora angustiora saepius linearia vel oblongo-linearia. Species 
typica P. obscura Benth. 
a. Capsule more or less pubescent on sides at maturity, 6. 
b. Hairs of stem all incurved or appresse 
c. Aril minute, capitelliform, scarcely lobed, d. 
d. Flowers 4-5 mm. lon _ Bere ee 22. P. magdalenae. 
a. Miowers 6-7 tim: 100s era ee. 23. P. leptosperma. 
. lon 
c. Aril lataie distinctly lols or lobulate, e 
e. Aril strongly 3-lobed, the lobes more or less ap- 
er, f. 
pr , slen 
f. Flowers 4-5 mm. iong Sere Pe 38. P. compacta. 
J. Slowers 6-7 mam, toned. ses os bs teks 39. P. polymorpha. 
e. Aril veil-like, merely lobulat 
g: — and wings quickly Aindaous core 32. P. obscura. 
Upper sepal — wits rather persistent ........ 34. P. Lozani. 
b. ‘Hair = cee nc least in part) wide-spreading 
es dimorphous of oe oval to oblong-ovel,, 
"oblong to lanceolate or linear), not retic ate; 
airs all short and spreading.............. 32.1. P. orthotricha. 
h. asta s not dimorphous, linear-lanceolate, Sg al 
— te; e; pubescence of short incurved and long 
31. P. retifolia. 
. P. leptosperma. 
is Pre ee Rony Lo eons pa 
h. een laneeolate to seRSEEIO Hs % —— 
. anaW BION ses is i a be ei ee 
i. Win os ceneiens at least at base, 7. 
¥. Anil small, the depth of the entire or merely seme 58% 
rneous umbo, k. ; 
k. ipitesehdins of short widely spreading hairs... .. 27.1. P. rectipilis. 
k. Hairs incurved o widely 
pe P. amphothriz = ; , P. chiapensis (no. 44), and P. trichoptera (no. 
might be sought hi 
