STANDLEY — TREES AND SHRUBS OF MEXICO. 523 



2. Guaiacum palmeri Vail, N. Amer. Fl. 25 : 107. 1910. 



Dry plains and hills, Sonora and Sinaloa ; type from Guaymas, Sonora. 

 Shrub or small tree; leaflets 4 to 10, 0.8 to 2.2 cm. long; petals blue, about 

 1.5 cm. long ; fruit 1 to 1.5 cm. long. 

 It is probable that this plant is only a form of O. coulteri. 



3. Guaiacum coulteri A. Gray, Mem. Amer. Acad, II. 5: 312. 1855. 

 Guaiacum planchoni A. Gray; Vail & Rydb. N. Amer. Fl. 25: 107. 1910. 

 Sonora to Ouxaca ; type collected between Rayon and Ures, Sonora. 

 Shrub or small tree, 1 to 12 meters high, with crooked branches; leaflets 



6 to 10, 1 to 2.5 cm. long, glabrous or nearly so; flowers fragrant, the petals 

 blue or violet, 1 to 1.5 cm. long; fruit about 1.5 cm. long. Known throughout 

 its range as " guayac^n ; " " arbol santo " (Puebla, Ramirez); " palo santo " 

 (Oaxaca, Jalisco); " matlaquahuitl " (Nalmatl, Ramirez); " yaga-na " (Oax- 

 aca, Zapotec, ReJco) ; " yutnu-taudaa " (Oaxaca, Mixtec, Reko). 



The plant was reported from Mexico by Mociiio and Sesse as G. afrum L. 

 The wood is hard and resinous, strong and durable, and is good for firewood, 

 being used sometimes for fuel in railroad engines. It is employed also for 

 making articles in which great strength is required. The tree is believed to 

 have essentially the same properties as G. sanctum. 



The writer has not seen type material of G. planchoni, which was described 

 from Oaxaca, but other material from that state differs in no way from 

 G. coulteri, and the characters supposed to separate the two species seem not 

 to hold in the material examined. 



5. SERICODES A. Gray, PI. Wright. 1 : 28. 1852. 



1. Sericodes greg-gii A. Gray, PI. Wright. 1: 28. 1852. 



Duraugo, Zacatecas, Coahuila, and Nuevo Leon; type from San Lorenzo 

 (Coahuila?). 



Low, densely branched shrub ; leaves fascicled, linear or oblanceolate, 8 

 to 12 mm. long, strigose ; flowers small, yellowish ; fruit a small capsule, sepa- 

 rating into 5 carpels, densely covered with long white hairs. 



6. MORKILLIA Rose & Painter, Smiths. Misc. Coll. 50': 33. 1907. 



Erect shrubs; leaves alternate, odd-pinnate, with large entire leaflets; flowers 

 very large, deep rose-purple, solitary or geminate ; fruit a large 4-winged capsule. 

 Leaflets acute or obtuse; wings of the fruit produced at the apex, the sinus 



narrow 1. M. mexicana. 



Leaflets acuminate ; wings of the fruit scarcely produced, the sinus broad 



and open 2. M. acum.inata. 



1. Morkillia mexicana (Moc. & Sesse) Rose & Painter, Smiths. Misc. Coll. 



50': 33. 1907. 



Chitonia mexicana Moc. & Sesse; DC. Prodr. 1: 707. 1824. 



Hidalgo, Puebla, and Oaxaca. 



Shrub, 3 to 5 meters high, with grayish white bark; leaflets 7 to 15, 3 to 

 5 cm. long, densely pubescent ; petals 3 to 4 cm. long ; fruit 4 to 6 cm. long. 

 " Guayacan " ( Oaxaca ) . 



2. Morkillia acuminata Rose & Painter, Smiths. Misc. Coll. 50': 34. 1907. 

 Known only from the type locality, mountains between Victoria and Jaumave 



Valley, Tamaulipas. 



Shrub, 3 to 5 meters high, densely pubescent; leaflets 3 to 9, 1 to 3 cm. 

 long ; petals 2.5 to 3 cm. long ; fruit 5 cm. long. 



