11; 



springs are scarce, and the vegetation dries up with surprising 

 quickness at the close of the rainy season. Nevertheless, while 

 the season lasts, this vegetation is fairly abundant and varied. 

 It is, moreover, rather peculiar to the region, therefore of special 

 interest. Not only the herbaceous vegetation, but the shrubs 

 and trees, are of strange relationship. Among the smaller trees, 

 an extremely poisonous species of Rhus is perhaps most notice- 

 able. Near the water the alligator pear grows spontaneously 

 and reaches a rather large size. The canyons and gulches are 

 full of beautiful white-flowered or violet-tinted acacias. A 

 small arborescent Malpighia, with edible fruit, is abundant. 

 The ground is covered in many places with gorgeous Tribulus, 



Fig. s. Balsas Mountains, Guerrero. 



in others with Ruellia, and very often with some plant related 

 to Allionia, but with handsome rose-purple flowers as large as 

 ordinary morning-glories. Many Asclepiadaceous vines twine 

 among the shrubbery. The Echinocacti are of peculiar type, 

 scarcely projecting above the ground and crowned with woolly 

 tufts. 



I twice visited Limon Mountain, about four miles from the 

 town of Balsas, and the crowning peak of the region. Its sides 

 are extremely steep and for the most part densely clothed with 



