STANDLEY TREES AND SHRUBS OF MEXICO. 897 



8. Pachycereus ruficeps (Weber) Britt. & Rose, Cactaceae 2: 75. 1920. 

 Pilocereus ruficeps Weber; Goss. Bull. Mus. Hist. Nat. 11. 509. 1905. 

 Cerens ruficeps Vaupel, Monatsschr. Kakteenk. 23: 27. 1913. 



Oaxaca and Puelba; type from Tehuacan, Puebla. 



Stout, columnar, 15 meters high, from a simple trunk, 30 to 40 cm. in diam- 

 eter, but branched above ; ribs about 26 ; young spines reddish ; radial spines 

 8 to 10, about 1 cm. long, rigid, grayish ; central spines 1 to 3, the longest 4 

 to 5 cm. long, porrect or deflexed ; flowers at the top of the plant, campanulate, 

 5 cm. long, the ovary and tube bearing small chartaceous scales, these with 

 small tufts of felt and a few yellow bristles in their axils; fruit small, not 

 edible; seeds small, brownish, shining. 



9. Pachycereus columna-trajani (Karw.) Britt. & Rose, Contr. U. S. Nat. 



Herb. 12: 421. 1909. 



Cereus columna-trajani Karw. ; Pfeiff. Enum. Cact. 76. 1S37. 



Pilocereus lateriiarbatus Pfeiff.; Forst. Handb. Cact. ed. 2. 672. 1885. 



Puebla and Oaxaca ; type from San Sebastian, Puebla. 



Plants erect, stout, up to 15 meters high, 45 to 50 cm. in diameter, often 

 simple ; ribs many, green ; areoles oblong, bearing brown felt ; radial spines 

 8 to 10, 12 to 25 mm. long; central spines more elongate, sometimes 16 cm. 

 long, deflexed ; spines all rigid, white or horn-colored except the brown bases 

 and tips, sometimes said to be soft and erect ; flowers described as purple. 

 "Tetetza" (Oaxaca, Gonzatti). 



DOUBTFUL SPECIES. 



Cereus tetazo Coulter, Contr. U. S. Nat. Herb. 3: .409. 1896. Pilocereus 

 tetetzo Weber; Schum. Gesamtb. Kakt. 175. 1897. Described from Jalisco. 

 This species has been referred to the present group, but the ovary is glabrous, 

 and the fruit fleshy and edible. It should be compared with Cephalocereus 

 macrocephalus. The names " tetetzo," " totazo," " cabeza de viejo," and 

 " tetecho " are reported for it. The fruits, known as " higos de tetetzo," are 

 edible, and are sometimes preserved by drying, and the flowers are said to be 

 eaten in salads. 



9. LEMAIREOCEEEUS Britt. & Rose, Contr. U. S. Nat. Herb. 12: 424. 1909. 



Plants usually large, tall, and branching, but rarely low, nearly prostrate, 

 simple, forming thickets; areoles rather large, felted; spines usually stout and 

 numerous ; flowers diurnal or in some species nocturnal, one at an areole, tubu- 

 lar-funnelform or campanulate, the short tube tardily separating with the style 

 from top of the ovary; stamens numerous, borne in many rows all along the 

 inner surface of the throat ; ovary more or less tubercled, bearing scales felted 

 in the axils, the areoles at flrst spineless or nearly so, soon developing a 

 cluster of spines ; fruit globular to oval, often edible, irregularly bursting when 

 old, exposing the seeds, at flrst very spiny, but when ripe the spines often 

 deciduous; seeds many, black. 



About 10 other species are known, widely distributed in tropical America. 



Ribs 5 to 7, separated by broad shallow intervals 11. L. dum.ortieri. 



Ribs 6 to 20, separated by deep intervals. 



Areoles with white, brown, or gray felt, not glandular. 



Spines very stout, at first reddish brown or nearly black 7. L. weberi. 



Spines slender, acicular to subulate. 

 Ribs about 20 6. L. treleasei. 



