CACTACEiE OF MEXICO SAFPORD. 



553 



Escontria includes a single species, the chiotilla, or xiotilla, of 

 southern Puebla and Oaxaca {Cereus chiotilla Weber). 



Carnegiea includes the giant sahuaro, or suguaro {Cereus gigan- 

 teus)^ already referred to, the fruit of which, called " pitahaya," is 

 an important food staple of the Indians, but is not so highly esteemed 

 as the pitahaya dulce of Lemaireocereus thurheri. 



Lemaireocereus, as proposed by Britton and Rose, includes plants 

 of widely different habits. Under this genus are placed the pitahaya 

 agria {Cereus gummosus Engelm.) and the chirinole, or chilenola, of 

 Lower California {Cereus eruca Brandeg.), both of them prostrate 

 plants with scarlet pitahayas containing pleasantly acid pulp; the 

 columnar pitahaya dulce of Sonora and Lower California {Cereus 

 thurheri Engelm.) ; and the pitahaya of Mexico and Central America, 

 Cereus griseus Haw. {C. ehurneus Salm-Dyck), figured by Rose in 

 vol. 12 of the Contributions from 

 the National Herbarium, pi. 67, 

 from a photograph taken by G. 

 N. Collins at El Rancho, near 

 Zacapa, Guatemala. Another 

 species assigned to the genus is 

 Cereus weheri Coulter {Cereus 

 candeldbrum Weber) , the massive 

 organo so characteristic of the 

 scenery about Tomellin, on the 

 way from Tehuacan to Oaxaca, 

 with its numerous thick crowded 

 vertical branches rising from a ^^^ i7.-Pachycei-eus pringiei, fruit. 



short central trunk. 



Peniocereus, with the single species Peniocereus greggli {Cereus 

 greggii Engelm.) is remarkable for the enormous fleshy root, from 

 which the slender 4-ribbed or 5 -ribbed stem rises. The large white 

 nocturnal flowers are remarkable for their very long slender tube, 

 bearing small clusters of spines on its outer surface. The ovoid, 

 long-acuminate scarlet fruit, bearing elevated spineless areoles, is 

 edible. Excellent figures of this plant are published by Rose (1. c, p. 

 428, plates 74 and 75) from photographs taken by Francis E. Lloyd 

 near Tucson. The range of the species extends to northern Mexico, 

 Texas, and Arizona. 



Hylocereus includes the well-known Cereus triangularis and Cereus 

 trigonus^ as well as C. ocamponis and C . napoleonis. There is much 

 confusion between the first two mentioned, but Hylocereus trigonus 

 (pi. 12), founded by Haworth on Plumier's plate 200, figure 2, pub- 

 lished in 1755, may be recognized by the salient points of its angular 



