618 CONTRIBUTIONS FROM THE NATIONAL. HERBARIUM. 



31. Croton xalapensis H. B. K. Nov. Gen. & Sp. 2: 85. 1817. 

 Veracruz to Chiapas ; type from Jalapa, Veracruz. Central America. 



Shrub or small tree, 2 to 9 meters higli, copiously stellate-tomentose, at least 

 when young ; leaves long-petiolate, cordate-ovate, 8 to 20 cm. long or larger, 

 acuminate or cuspidate-acuminate; racemes very long and slender. " Targua," 

 " terre," " targuacillo " (Costa llica) ; " chirca " (Guatemala, Honduras). 



The wood is white and wealv. The gum which exudes from the trunk is used 

 for cleaning the teeth. 



32. Croton subfragilis Muell. Arg. Linnaea 34: 111. 1865. 

 Known only from the type locality, between Tuxtla and Chiapas. 



Leaves oblong-ovate, 10 to 15 cm. long, cuspidate-acuminate, stellate-pubescent 

 with ferruginous hairs. " Copalchi." 



33. Croton mexicanus Muell. Arg. Linnaea 34: 113. 1865. 

 Described from Mexico, the locality not known. 



Leaves oblong-ovate, 12 cm. long or shorter, stellate-pubescent with depressed 

 hairs or glabrate, acuminate, entire or denticulate. 



34. Croton cladotrichus Muell. Arg. Linnaea 34: 124. 1865. 

 Croton purpusii T. S. Brandeg. Univ. Calif. Publ. Bot. 6: 184. 1915. 

 Michoacan to Oaxaca. 



Shrub, copiously stellate-pubescent or tomentose, the branches covered with 

 thick corky bark ; leaves mostly suborbicular, 6 to 15 cm. long, usually abruptly 

 short-pointed, more or less cordate at base ; spikes usually shorter than the 

 leaves, very thick and dense. " Gordolobo " (MichoacSn, Guerrero). 



35. Croton francoanus Muell. Arg. Linnaea 34: 124. 1865. 

 Known only from the type locality, near Oaxaca. 



Leaves nearly sessile, broadly triangular-ovate, 5 to 10 cm. long, acuminate, 

 cordate at base, whitish-tomentose beneath. 



36. Croton corymbulosus Engelui. in AMieeler, Rep. U. S. Surv. 100th Merid. 

 5: 242. 1878. 



Chihuahua, Coahuila, and Sonora. Western Texas to southern Arizona; type 

 from Camp Bowie, Arizona. 



Plants low, woody at base, the stems clustered, densely silvery-pubescent 

 throughout ; leaves long-petiolate, orbicular to oblong, 2 to 4.5 cm. long ; racemes 

 2 to 4 cm. long. "Encinilla " (Texas). 



Tea made from the leaves is used in domestic medicine in western Texas, be- 

 cause of its sudorific and tonic properties. 



37. Croton ehrenbergii Schlecht. Linnaea 19: 248. 1847. 

 Hidalgo. 



Slender shrub, 0.6 to 1.2 meters high ; leaves short-petiolate, 1 to 3 cm. long, 

 entire, densely silvery-pubescent beneath ; racemes short, few-flowered. 



38. Croton torreyanus Muell. Arg. in DC. Prodr. 15=*: 579. 1866. 

 Coahuila and Nuevo Leon to Veracruz. Western Texas (type locality). 

 Shrub, 1 to 2 meters high, stellate-tomentose ; leaves short-petiolate, 3 to 6 



cm. long, entire; racemes 1 to 4 cm. long. " Salvia " (Tamaulipas). 



39. Croton alamosanus Rose, Contr. U. S. Nat. Herb. 1 : 111. 1891. 

 Sonora to Oaxaca ; type from Alamos, Sonora. 



Shrub, 1 to 4 meters high ; leaves nearly sessile, ovate or oblong-ovate, 5 to 

 14 cm. long, cordate at base, long-acuminate, green, thinly stellate-pubescent, 

 entire or nearly so. " Ocotillo " (Sinaloa). 



The resin is employed as a remedy for toothache. 



