24 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
treatment of the species is not very satisfactory. He recognizes but 
six species belonging to this genus, five of which are credited to 
Mexico. 
The writer has seen at least cleven species of Argemone from Mex- 
ico and nearly all of them he has actually collected. Several other 
species have been described by various writers, but these are not vastly 
made out. They have all gone into synonymy, where perhaps they 
should remain. All of the species are common and the genus has a 
wide distribution, both laterally and altitudinally. The various species 
seem to prefer cultivated ground to the unbroken soil and are there- 
fore most commonly found in neglected fields and along railroad tracks. 
If Mr. A. Nelson’s genus Enomeera based on Argemone hispida pos- 
sesses no other characters than those cited in the original place of pub- 
lication, viz, thick milky-white sap and densely bristly stems and leaves, 
it can hardly be taken seriously. 
KEY TO SPECIES. 
Flowers yellow. 
Seis woody... 0.2222 eee Il. A. fruticosa, 
Stems herbaceous. 
Styles none; flowers bright yellow... 00.2222 ee 2. L. mericana. 
Style evident; Jlowers pale yellow .. 0.0 00202.-22----------- 22. 3B. vl. ochrolenea, 
Flowers not yellow (mostly white) . . 
Back of sepals not prickly; fruit nearly smooth .22..02222.000---. 4.0. grandiflora. 
Back of sepals more or less prickly; fruit prickly. 
Flowers pinkish ov purple .....0.202202-----2----- 2 5. A, senguinea. 
Flowers white. 
Stems and leaves setose as well as densely prickly. ...2.0.0..-----. 6. A. hispida, 
Stem and leaves not setose and less densely prickly. 
Filaments purple. 
Style slender... 2.00.0. oo eee 7. A. arida, 
Style wanting 2.2.2.0... cee eee eee 8. o1. platyceras, 
Filaments yellow. 
Petals small and narrow... 2.02.02... 2.222.222 9. A. stenopetala, 
Petals large and broad, 
Steins stout, very prickly... 0.00.22. 2-2-2222. LO. A. amunita. 
Slems weak, much less prickly. ....2...2.--------2 Il. A. gracilenta, 
1. Argemone fruticosa Thurber; Gray, Mem. Am. Acad. 11. 5 : 806. 1854. 
Speciinen evramined: 
Coahuila: At San Lorenzo de Laguna, E. Palmer 21, 1880 
Type locality: “In the mountain pass of La Pena, Coahuila.”’ 
2. Argemone mexicana L. Sp. Pl. 1 :508. 1753. 
Type locality: ‘Mexico, ete.” 
The writer, who has traveled extensively over Mexico and has looked expressly 
for this species, has never seen it in all the western or central part of the country. 
Indeed, he has only once collected it and then about Oaxaca City, where it could 
easily haye been introduced. These observations are in line with Prain, who states 
that the species is found in Mexico only as an introduced plant, generally in the 
neighborhood of seaport towns. 
All herbarium material seen is from Guatemala and extreme south Mexico. 
