CEPHALOCEREUS. 41 



19. Cephalocereus monoclonos (De Candolle) Britton and Rose, Contr. U.S. Nat. Herb. 12: 418. 1909. 



Cereus monoclonos De Caiulollc, Prodr. 3: 464. 1828. 

 Melocactns monoclonos Steudel, Nom. cd. 2. 2: 122. 1841. 



vStems simple, erect, tall, mostly 8-ribbed; ribs triangular in section, high, obtuse; spines 10 

 to 1 6, short, about equal, spreading; flowering areoles with only a few short hairs; flower-tube 

 short and thick, bearing a few broad, pointed scales; perianth-segments white, numerous, spread- 

 ing, retuse; stamens not exserted, numerous; style slender, long-exserted, with 5 or 6 stigma-lobes; 

 fruit purple, globular, naked, thick-walled, with numerous shining seeds. 



Type locality: Caribbean Islands, according to De Candolle. 



Distribution: Probably Hispaniola. 



There are probably two species of this genus on Hispaniola, although a half-dozen 

 species have been described, two of them based on the same illustration. We believe that 

 (.". monoclonos is one of these. De Candolle, however, who first took up this species under 

 Cereus, and who knew it only from Plumier's description and his somewhat convention- 

 alized plate, gave its range as Caribbean Islands, but since most of Plumier's plates are 

 supposed to be based on Hispaniola plants, it should be looked for on that island; however, 

 explorations on both sides of the island in recent years have failed to bring it to light. 



Illustration: Plumier, PI. Amer. ed. Burmann, pi. 191. 



Figure 58 is copied from Plumier's plate above cited. 



20. Cephalocereus scoparius (Poselger) Britton and Rose, Contr. U. S. Nat. Herb. 12: 419. 1909. 



Pilocereus scoparius Poselger, Allg. Gartenz. 21: 126. 1853. 

 Cereus scoparius Berger, Rep. Mo. Bot. Card. 16: 63. 1905. 



"Arborescent; much branched, 20 to 25 feet high. Trunk a foot and more in diameter. 

 Branches often very long, 2 to 3 inches in diameter. The younger branches, which have not yet 

 borne flowers, are somewhat different from the older ones which have borne flowers. The former 

 (younger) have 12 to 15 ribs. Ribs blunt, the furrows tolerably sharp. Areoles 8 to 12 lines apart, 

 naked, somewhat thickened and protruding, close under the areole a strongly marked horizontal 

 impression, through which the ribs appear serrated. Radial spines 5, somewhat bent downward, 

 2^2 to 4 lines long. Central spine i, stout, sharp, bent upward, blackish when young, later whitish, 

 i inch long. The latter (older) flower-bearing branches are usually thinner, having 20 to 25 ribs; 

 these are lower, blunter, and much closer together. Areoles very thick. Radial spines 5 to 7, 

 central spine i, all of the spines 10 to 15 lines long, bristle-like, brown. Flowers very sparse, small, 

 almost campanulate (bell-shaped) reddish. Fruit red, of the size of a hazel-nut. Seeds large, 

 black, shiny." This is a translation of the original description. 



Type locality: Near La Soledad (near Vera Cruz, Mexico). 



Distribution: Known only from the type locality. 



Pilocereus sterkmannii Hortus is an unpublished name cited in the synonymy of P. 

 scoparius by Schumann (Gesamtb. Kakteen 179. 1897). 



We know the plant only from description. Schumann (Gesamtb. Kakteen 179) 

 states that the flowering tops have up to 25 ribs. 



21. Cephalocereus moritzianus (Otto). 



Cereus moritzianus Otto in Pfeiffer, Entim. Cact. 84. 1837. 

 Pilocereus moritzianus Lemaire, Illustr. Hort. 13: under pi. 469. 1866. 



Tree-like, up to 10 meters high, sometimes with 50 ascending branches, green or bluish; ribs 

 7 to 10, obtuse, separated by acute intervals; areoles 10 to 12 mm. apart, all white-woolly at first; 

 flowering areoles with tufts of wool i cm. long or longer; spines slender, at first brownish, rigid, 

 straight, i to 3.5 cm. long; radial spines 6 to 8; central spines 3; flowers 5 cm. long, the outer 

 perianth-segments broad, short, the inner white, obtuse; fruit red, depressed, naked, 4 to 5 cm. 

 broad. 



Type locality: La Guayra, Venezuela. 



Distribution: Venezuela; northwestern mainland and Bocas Islands of Trinidad; 

 Tobago. 



