3Q 



THE CACTACEAK. 



Illustrations: Vellozo, Fl. Flum. 5: pi. 20, as Cactus melocactus; Martius, Fl. Bras. 

 4 2 : pi. 43; Engler and Prantl, Pflanzenfam. 3 6a : f. 65, b, as Cephalocereus melocactus; Mo- 

 natsschr. Kakteenk. 3: 25, as Pilocereus melocactus. 



Figure 29 is from a photograph taken at Rio de Janeiro by Paul G. Russell in 1915; 

 figure 26 shows the fruit as drawn by A. Lofgren. 



Cereus ferox Haworth (Phil. Mag. 7: 109. 1830) may be of this relationship. It is 

 described as upright, stout, oblong, terete, 9 inches high, 2 inches in diameter, dark green; 

 ribs about 18, densely covered with spreading yellow spines; radial spines about 6; central 

 spines 4 or 5, one twice as long as the others, much stouter, up to an inch long. This 

 species was introduced from Brazil by Loddiges, in whose collection it was seen and 

 described by Haworth. It is stated to be near Cereus multangularis , Forster and Schu- 

 mann did not know the species. 



5. Cephalocereus dybowskii (Gosselin). 



Cereus dybowskii Gosselin, Bull. Soc. Bot. France 55: 695. 1908. 

 Stems much branched at the base, sending up many strict, usually simple branches 2 to 4 

 meters high, 8 cm. in diameter, almost hidden by the white cobwebby hairs of the areoles; ribs 

 numerous, often 23, low; pseudocephalium on the west side of the plant, consisting of a mass of long 

 white wool extending from the top of the branch downward sometimes for 5 to 6 dm. ; spines yellow, 

 the radials short, hidden in the white hairs, the central spines 2 or 3, porrect, acicular, 2 to 3 cm. long; 

 flower opening at night, 4 cm. long; inner perianth-segments white, broad, short; stamens in 2 

 series; stamens in upper series with short filaments or none; stamens in lower series united at base 

 into a short tube; style slender, cream-colored, 3.5 cm. long; stigma-lobes about 15, linear; fruit 

 globular, naked, pinkish, 2.5 cm. in diameter; seeds black, roughened. 



Fig. 30. — Cephalocereus dybowskii. 



Type locality: Itumirin, Bahia, Brazil. 



Distribution: Common on the dry hills in Bahia, where it forms dense thickets some- 

 times to the exclusion of all other plants. 



Our description is based largely on the specimens collected by Dr. Rose at Barrinha, 

 Bahia, in 1915 (No. 19785). 



In Bahia this species is called cabeca branca or mandacaru de penacho. 



Figure 30 is from a photograph taken at Barrinha, Bahia, by Paul G. Russell in 1915. 



