CEPHALOCEREUS. 27 



1. Cephalocereus senilis (Haworth) PfeifFer, Allg. Gartenz. 6: 142. 1838. 



Cactus senilis Haworth, Phil. Mag. 63: 31. [824. 

 Cactus bradypus Lehmann, Ind. Sem. Hamburg 17. 1826. 

 Cereus .senilis Dc Candolle, Prodr. 3:464. 1828. 

 Cephalophorus senilis Lemaire, Cact. Aliq. Nov. xii. 1838. 

 Pilocereus senilis Lemaire, Cact. Gen. Nov. Sp. 7. 1839. 

 Echinocactus senilis Beaton, Loudon's Gard. Mag. 15: 550. 1839. 

 Echinocaclus staplesiae Tate, Loudon's Gard. Mag. 16: 27. 1840. 



Plants 6 to 10 or even 15 meters high, columnar, simple or rarely branched above, sometimes 

 branched at base; ribs numerous; pseudocephalium developing on plants when 6 meters high, 

 broadening above, rarely confined to one side but usually encircling the top of the plant; areoles 

 closely set; the ones at base of old plants producing weak, gray bristles 2 to 3 dm. long, the ones 

 in the pseudocephalium producing similar but shorter bristles intermixed with dense, tawny wool, 4 

 to 6 em. long; flower, including the ovary, 5 cm. long, rose-colored; scales few on the tube; fruit 

 obovoid, 2.5 to 3 cm. long, rose-colored, capped by the chartaceous base of the flower, bearing a 

 few minute scales with hairs in their axils. 



Type locality: Mexico. 



Distribution: Hidalgo and Guanajuato, Mexico. 



Cephalocereus senilis has long been considered a great curiosity and small plants are 

 shipped in quantities to Europe. The young plants are covered with long white silky hairs 

 resembling a beard and hence the name old man cactus, and similar names. Large plants 

 are not often seen since the species grows in regions difficult of access. It is very common 

 on limestone hills of eastern Hidalgo, where it is often the most conspicuous plant in the 

 landscape. Large individuals are common here and are often 15 meters high. Very little 

 wood-tissue is developed and the largest individuals can easily be cut down with a pick or 

 small knife. 



Salm-Dyck (Cact. Hort. Dyck. 1844. 24. 1845) named two varieties of Pilocereus 

 senilis: longispinus and flavispinus; later (Cact. Hort. Dyck. 1849. 40, 186. 1850) he 

 described P. senilis longisetus, saying nothing about longispinus and flavispinus. 



Cereus bradypus Lehmann and Melocactus bradypus Lehmann (Steudel, Nom. ed. 2. 

 1: 333. 1840; 2: 122. 1841) are cited as synonyms of Cereus senilis. 



Illustrations: Schumann, Gesamtb. Kakteen f. 40; Grassner, Haupt-Verz. Kakteen 

 2; Knippel, Kakteen pi. 1; Engler and Prantl, Pflanzenfam. 3 6a : pi. opp. p. 180; f. 60; 

 Safford, Ann. Rep. Smiths. Inst. 1908: f. 15, 16, all as Cephalocereus senilis; Forster, Handb. 

 Cact. ed. 2. f. 91, 92; Monatsschr. Kakteenk. 4: 124, 125; Rev. Hort. 61 : f. 139; 62:f. 38, 

 39; Rumpler, Sukkulenten f. 78; Diet. Gard. Nicholson Suppl. f. 634, all as Pilocereus 

 senilis; Monatsschr. Kakteenk. 1:32, as Pilocereus senilis cristatus; Nov. Act. Nat. Cur. 

 16: pi. 12, as Cactus bradypus. 



Figure 24 is from a photograph of a small plant in the collection of the New York 

 Botanical Garden. 



2. Cephalocereus hoppenstedtii (Weber) Schumann in Engler and Prantl, Pflanzenfam. 3 6a : 181. 



1894. 



Pilocereus hoppenstedtii Weber, Cat. Pfersdorff. 1864 (according to Schumann). 



Pilocereus hagendorpi Regel, Gartenflora 18: 220. 1869. 



Pilocereus lateralis Weber, Diet. Hort. Bois 966. 1898. 



Cereus hoppenstedtii Berger, Rep. Mo. Bot. Gard. 16: 70. 1905. 



Slender, columnar, said sometimes to reach 10 meters in height, but in cultivation much lower, 

 often bent or clambering, the apex tapering; ribs low, close together, 20 or more, the whole plant 

 hidden under the numerous spines; areoles close together; radial spines 14 to 18, very short, white; 

 central spines 5 to 8, the longest one sometimes 7.5 cm. long, usually reflexed, brownish; pseudo- 

 cephalium at the top of the plant but to one side (said to be on the north side) ; flower described as 

 7.5 cm. long, whitish, with rosy tips, bell-shaped; fruit not known. 



Type locality: Zapotitlan, near Tehuacan, Mexico. 



Distribution: Southern Mexico. 



This plant is clearly a close relative of Cephalocereus senilis. 



