MYRTIIXOCACTUS. 



•79 



Typo species: Cereus geometrizans Martius. 



This genus has no very close allies. We have grouped it with Lophocereus and the fol- 

 lowing genus, because they likewise have more than 1 flower from an areole, but otherwise 

 little else in common. The small flowers somewhat resemble orange flowers, having scarcely 

 any tubes; the short stamens are almost entirely exserted. The fruits are small berries. 



We know 4 closely related species, natives of Mexico and Guatemala. The name is 

 from the Greek, signifying berry-cactus, referring to the small fruit. 



Fig. 252. — Cross-Section of stem of 

 Lophocereus schottii. X0.5. 



Fig. 253. — Flower 

 of Lophocereus 

 schottii. Natural 

 size. 



Fig. 254. — Section of rib of Myrtillo- 

 cactus geometrizans with fruit at the 

 areoles. X0.8. 



Fig. 255. — Flower of same. X0.8. 



Key to Species. 



Young branches very blue; central spine elongated, reflexed, dagger-like 1. M. geometrizans 



Young branches green; central spine not dagger-like. 



Spines usually 3 to 5, ascending, with no definite central spine or, when present, very short. .2. M. cochal 

 Spines 6 or more, with definite central spine. 



Radial spines 5; fruit oblong, 10 to 15 mm. long 3. M. schenckii 



Radial spines more than 5; fruit globular, 6 mm. in diameter 4. M. eichlamii 



1. Myrtillocactus geometrizans (Martius) Console, Boll. R. Ort. Bot. Palermo i: 10. 1897. 



Cereus geometrizans Martius in Pfeiffer, Enum. Cact. 90. 1837. 



Cereus pugioniferus Lemaire, Cact. Aliq. Nov. 30. 1838. 



Cereus gladiator Otto and Dietrich, Allg. Gartenz. 6: 34. 1838. 



Cereus geometrizans pugioniferus Salm-Dyck, Cact. Hort. Dyck. 1849. 48. 1850. 



Cereus geometrizans quadrangularispinus Lemaire in Labouret, Monogr. Cact. 367. 1853. 



Tree-like, with a short definite trunk crowned by a large, much branched top; branches often 

 a little curved, bluish green, usually 5 or 6-ribbed, 6 to 10 cm. in diameter, very blue when young; 

 ribs 2 to 3 cm. high, rounded; areoles 2 to 3 cm. apart; radial and central spines very different, almost 

 filling the areoles; radial spines usually 5, rarely 8 or 9, usually short, 2 to 10 mm. long, but some- 

 times 3 cm. long, more or less turned backward, a little flattened radially but swollen at base; central 

 spine elongated, dagger-shaped, flattened laterally, 1 to 7 cm. long and sometimes 6 mm. broad; 

 flowers appearing from the upper part of the areole, 2.5 to 3.5 cm. broad, the limb 3 to 4 times as 

 long as the tube; perianth-segments oblong, 1.5 cm. long; stamens numerous, erect, exserted; fruit 

 ellipsoid to subglobose, edible, purplish or bluish, 1 to 2 cm. long. 



Type locality: Mexico. 



Distribution: San Luis Potosi to Oaxaca, Mexico. 



This cactus is very common on the Mexican tableland. The fruits, known as garram- 

 bullas, are to be found in all the Mexican markets, and are eaten both fresh and dried; the 

 dried fruits very much resemble raisins in appearance and are used in much the same way. 



