360 APPENDIX. 
vions on the Colorado; beginning to flower in January. Resembles the original specimens 
collected on the Gila by Major Emory. 
SIDA HEDERACEA, Torr. in Pl. Fendl. p. 23. River bottoms near Fort Yuma, and west to the 
Pacific; August, September. 
HIBISCUS DENUDATUS, Benth. Bot. Sulph. p. 7, t. 3. California desert, January, May. 
Darra EmorY1, Gray, Pl. Thurb. p. 315. Sandy soils on the Colorado and Gila. This and 
the following species, viz: D. spinosa, Gray; D. scoparia, Gray; D. frutescens, Gray; D. 
arborescens, Torr.; D. Fremontii, Torr.; and D. Schottii, n. sp., form a peculiar group, inter- 
mediate between Dalea and Psoralea, distinguished from the former by the truly papilionaceous 
corolla, and by all the petals being inserted at the base of the calyx ; from the latter, (at 
least the North American species,) in habit, in the monadelphous stamens, the upper part 
of the filaments being distinct, and in other characters. Other remarks on this group will bo 
made in the botany of the Mexiean Boundary Survey. (Tab. II.) 
Darra mous, Benth. Pl. Hartw. p. 306. With the last; a smaller plant than the New 
Mexican variety. / 
CERCIDIUM FLORIDUM, Benth. Mss.; Gray, Pl. Wright, p. 58, (adnot.) On the Colorado, and 
in the desert west. Itis called Palo verde by the Mexicans, and @reen Acacia by the Ameri- 
cans. It sometimes attains the height of 30 feet. (Tab. III.) 
LUPINUS SPARSIFLORUS, Benth. Pl. Hartw. p.303. On the Colorado. Less hairy than the 
plant described by Bentham. 
STROMBOCARPA PUBESCENS, Gray, Pl. Wright, 1, p. 60. Prosopis (Strombocarpa) pubescens, 
Benth. in Lond. Jour. Bot. 5, p. 82. This is the well known Screw-bean of travellers in New 
Mexico and California. It occurs from the Rio Grande to the western slope of the Cordilleras 
of California. The pods are an important article of food to the Mexicans and Indians, and are 
also greedily eaten by cattle. (Tab. IV.) 
OPUNTIA TESSELLATA, Engelm. Syn. Cact. p. 53, & in Cact. Whippl. Pacif. Railroad Surv. 
1. 21. Desert west of the Colorado. A remarkable species; weil described and figured by 
Engelmann. 
MAMMILLARIA PHELLOSPERMA, Engel. Cact. Mex. Bound. p. 6, t. T. Common on the Colorado. 
MENTZELIA ALBICAULIS, Torr. & Gray, Fl. l, p. 534. Sandy soils; from the Gila to San 
Diego; beginning to flower when scarcely an inch high. 
MENTZELIA PUMILA, Nutt. in Torr. & Gray, Fl. 1,c. On the Colorado; beginning to flower 
in March. This agrees with Nuttall's original specimens, and with others collected in Califor- 
nia by Frémont. 
(ExorHERA (CHYLISMIA) CLAVAFORMIS, Torr. de Frem. in Frem. 2d Hep. p.314. With the 
last. Anthers hairy. We fear that R. brevipes of the Botany of Whipple's Expedition is p state 
of this species with considerably larger flowers and short pedicels. Intermediate specimens 
seem to connect them. We have a remarkable variety, collected by Frémont in 1849, (probably 
on the Lower Gila,) in which the lamina of the leaf is more than six inches long, deeply pin- 
natifid, the segments very unequal and coarsely toothed, the terminal one scarcely larger than 
some of the others. 1 
CENOTHERA (CHYLISMIA) CARDIOPHYLLA (n. sp.): annua, caule folioso parce ramoso; nues 
cordatis repando-dentatis, petiolo nudo ; capsulis elongato-cylindricis subsessilibus v. pedicello 
3-4-0 longioribus. Near Fort Yuma. Whole plant, when young, clothed with a soft white 
 pubescence, most of which disappears with age. Stem 6-12 inches high. Leaves deeply cordate, 
