7 2 



THE CACTACEAE. 



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Fig. 106. — Fruit of Pachycereus pecten-aboriginum. 



5. Pachycereus grandis Rose, Contr. U. S. Nat. Herb. 12: 421. 1909. 



Cereus bergerianus Vaupcl, Monatsschr. Kakteenk. 23: 24. 1913. 



Plant 6 to 10 meters high, either simple or much branched, the trunk sometimes a meter in 

 diameter ; branches, when present, columnar, generally simple, becoming erect almost from the first, 

 with numerous constrictions, pale green, or when young glaucous, with some bloom which persists 

 in streaks; ribs 9 to 11, acutish, high; sterile areoles circular, large, bearing white felt and subulate 

 spines, 2 to 3 cm. apart, not running together, not extending below the spines as in P. pecten- 

 aboriginum; old spines grayish to white with black tips; radial spines 9 or 10; central spines 3, the 

 lower one longer, sometimes 6 cm. long, somewhat flattened ; flowering areoles large, elliptic, bearing 

 acicular or bristle-like spines; flowers rather small for the genus, about 4 cm. long; ovary and flower- 

 tube bearing small, acuminate scales, their axils filled with downy hairs; fruit large, globular, dry, 

 covered with long yellow bristles and yellow felt. 



Type locality: On the pedregal near Cuernavaca, Mexico. 



Distribution: Common in the State of Morelos, Mexico. 



This plant is very common on the pedregal north of Cuernavaca, where it was first 

 observed by Dr. Rose in 1906 (No. 1 1087) , and is frequent on the hills south of Cuernavaca. 

 Mr. Dowell, the cactus dealer in Mexico City, told Dr. Rose that he had exported plants 

 to Europe, but whether they are now in the trade we do not know. A living specimen sent 

 back by Dr. Rose has since been growing in the Washington Botanical Garden. 



6. Pachycereus chrysomallus (Lemaire) Britton and Rose, Contr. U. S. Nat. Herb. 12: 421. 1909. 



Pilocereus chrysomallus Lemaire, Fl. Serr. 3: under pi. 242. 1847. 

 Cereus chrysomallus Hemsley, Biol. Centr. Amer. Bot. 1: 541. 1880. 

 Cephalocereus chrysomallus Schumann in Engler and Prantl, Pflanzenfam. 3 C| 

 Pilocereus fulviceps Weber in Schumann, Gesamtb. Kakteen 176. 1897. 

 Cereus fulviceps Berger, Rep. Mo. Bot. Gard. 16: 64. 1905. 



1894. 



Stem columnar, massive, at first simple, but in very old plants much branched, giving off 

 hundreds of erect branches which form an almost compact cylinder up to 5 meters in diameter, 

 becoming 12 to 18 meters high; branches glaucous green, 1 1 to 14-ribbed; flowering branches capped 



