56 



the; cactaceae. 



In our original description we referred here specimens from northern Colombia which 

 we now include in Cephalocereus russelianus. 



Illustrations: Contr. U. S. Nat. Herb. 12: pi. 62, 63. 



Figure 82 is from a photograph of the plant; figure 83 a. shows a piece of the stem; 

 figure 83 b a cross-section of the stem; figure 83 c a flower; and figure 83 d a flower-bud; 

 all are from photographs of the type specimen by Henry Pittier. 



44. Cephalocereus purpusii sp. nov. 

 Stems slender, 2 to 3 meters high, sim- 

 ple or more or less branched ; branches green, 

 erect, 3 to 4 cm. in diameter, usually sim- 

 ple; ribs 12, low, 5 to 6 mm. high, separated 

 by narrow intervals; areoles closely set, 10 

 mm. apart or less on the lower part of the 

 stem, but much closer together toward the 

 top, on the young growth with long silky 

 white hairs, but on old parts without hairs; 

 spines acicular, swollen at base, 1 to 3 cm. 

 long, bright yellow at first, in age gray. 



Collected by Rose, Standley, and 

 Russell at Mazatlan, Mexico, on the 

 hills near the town overlooking the sea, 

 March 31, 1910 (No. 13749, type), and 

 also a short distance inland at Guada- 

 lupe, in thickets, April 18, 19 10 (No. 

 14741). 



This species differs from the other 

 Mexican ones in having very slender 

 stems. It is named for the veteran col- 

 lector, Dr. C. A. Purpus, who writes 

 that he collected the species several 

 years earlier than above recorded. We 

 have not, however, seen his specimens. 



The plant is growing in the New 

 York Botanical Garden, from Dr. Rose's 

 collection at Mazatlan. 



45. Cephalocereus catingicola (Gurke). 



Cereus catingicola Gurke, Monatsschr. Kakteenk. 18: 54. 1908. 

 Tree-like, 3 to 10 meters high, with a short definite trunk and a large, much branched top, 

 bluish green; ribs 4 or 5, separated by broad intervals; areoles large, woolly; spines yellow when 

 young, numerous, unequal, the longest 3 cm. long; flowers 6 to 8 cm. long, 6 cm. broad when fully 

 open, with a broad throat, opening in the evening, odorless ; flower-tube short, about 1 cm. long, with 

 broad scales near its top, these green with brownish margins ; perianth-segments numerous, broad, 

 short, white, stiff; anthers dehiscing soon after the flowers open; filaments short, the lower ones 

 much longer than the upper one but all included, attached all over the throat; style stout, soon 

 exserted, at first raised against the upper part of the throat, white; stigma-lobes at first white but 

 pinkish the second day after anthesis ; fruit broader than high, glaucous, 6 to 7 cm. broad, capped by 

 the withered perianth; rind thick; pulp purple. 



Type locality: In the caatinga of Bahia, Brazil. 



Distribution: Common in the caatinga of Bahia. 



Illustration: Monatsschr. Kakteenk. 18:55, as Cereus catingicola. 



Plate viii, figure 2, shows the top of a plant brought from Bahia by Dr. Rose in 1915. 



Fig. 83. — Cephalocereus colombianus. 



