STANDLEY TKEES AND SHRUBS OF MEXICO. 429 



Pedicels glabrous or with few scattered appressed hairs 1. C. floridum. 



Pedicels copiously pilose with very short spreading hairs. 

 Younger branches densely pilose with short whitish hairs. 



2. C. peniusulare. 

 Younger branches glabrous or nearly so, sometimes finely pnberulent. 



Pods turgid when mature; seeds 5 to 7 mm. wide 3. C. torreyanum. 



Pods very flat; seeds about 3.5 mm. wide 4. C. plurifoliolatum. 



1. Cercidium floridum Benth. ; A. Gray, PI. Wright. 1 : 58. 1852. 

 Coahuila to Tamaulipas. Southwestern Texas. 



Spiny tree with crooked branches, sometimes 6 meters high, the trunk up 

 to 25 cm. thick ; bark thin, green ot greenish brown ; leaflets 2 to 4 pairs, 4 

 to 6 mm. long; flowers golden yellow, about 2 cm. broad, sweet-scented, in 

 short racemes ; fruit 4 to 6 cm. long, brownish yellow ; wood soft, close-grained, 

 greenish yellow, with a specific gravity of about 0.54. "Retama" (Tamaulipas) ; 

 " palo verde " (Texas). 



The wood is of little use except for fuel. 



2. Cercidium peninsulare Rose, Contr. U. S. Nat. Herb. 8: 301. 1905. 

 Southern Baja California, common at low and middle elevations ; type from 



La Paz. 



Shrub or small tree, 1 to 7.5 meters high, closely resembling the next species 

 and doubtfully distinct from it ; spines short and stout ; leaflets 5 to 10 mm. 

 long, pubescent. " Palo verde," " palo de ptia." 



The young branches are sometimes cut and fed to horses and mules. For an 

 illustration of a tree see Contr, U. S. Nat. Herb. 16: pi. 114- 



3. Cercidium torreyanum (S. Wats.) Sarg. Gard. & For. 2: 388. 1889. 

 Parkivsonia torrei/ana S. Wats. Proc. Amer. Acad. 11: 135. 1876. 



Sonora to Tepic. Southern Arizona (type from the Lower Colorado River) 

 and California. 



Small tree, sometimes 9 meters high, with a trunk 50 cm. in diameter; bark 

 bright green; leaflets 2 or 3 pairs, 3 to 6 mm. long; fruit 8 to 10 cm. long, 

 about 1 cm. wide; wood soft, weak, close-grained, light brown, with yellow 

 sapwood, the specific gravity about 0.65. "Palo verde" (Sonora, California, 

 Arizona ) . 



The Indians of Arizona ground the fruit in a mortar and used it for food, 

 especially in the form of atole. The wood was employed for various purposes. 



4. Cercidium plurifoliolatum IMicheli, M^m. Soc. Phys. Nat. Hist. Geneve 



34: 269. pi. J8. 1903. 



Cercidium goldmani Rose, Contr. U. S. Nat. Herb. 8: 301. 1905. 



Cercidium unijuga Rose, Contr. U. S. Nat. Herb. 8: 301. 1905. 



Michoacan to Puebla and Oaxaca ; type from San Luis (Guerrero ?). 



Tree. 4.5 to 12 meters high, the green branches armed with stout spines ; 

 leaflets mostly 5 to 8 pairs, 5 to 8 mm. long, pubescent ; fruit thin, 4 to 7 cm. 

 long, 8 mm. wide. "Palo de berria," " mantecoso," "palo mantecoso " (Oax- 

 aca). 



67. FABACEAE. Bean Family. 



Trees or shrubs, often scandent ; leaves alternate, stipulate, usually com- 

 pound ; flowers often large and showy, very irregular ; fruit a legume, some- 

 times variously modified. 



One of the largest and most important groups of Mexican plants. Many 

 herbaceous species occur also. Perhaps some species of genera not included 

 here, especially of Phascoius, deserve to be classed as shrubs. Two species of 

 Ormocarpum have been reported from Mexico, but they are unknown to the 



