n6 



THE CACTACEAE. 



preference for soft parts of the coastal plain and grow usually in groups, often topping a slight 

 eminence formed of wind-drifted material. These cactuses serving as a sand binder and preventing 

 erosion tend to favor further accumulations. The desert foxes (Vulpes macrotis devius) of the region 

 find congenial burrowing places among the procumbent trunks." 



Illustrations: Monatsschr. Kakteenk. 5:71; Proc. Calif. Acad. II. 2: pi. 7; Schumann, 

 Gesamtb. Kakteen f. 29; Nat. Geogr. Mag. 22: 466, as Cereus eruca; Contr. U. S. Nat. 

 Herb. 16: pi. 127, as Lemaireocereus eruca. 



Figure 171 is from a photograph taken by E. A. Goldman at Santo Domingo, Lower 

 California; figure 172 is from a photograph of a plant collected by C. R. Orcutt at Magda- 

 teria Bay, Lower California. 



J^kd 







isiifi 





















^S&SfSt^&'imj^Sf&^^tSS^^^ 



n^fk 



®*ffi^l 



Wml 



vevy] 



Kill 







Fig. 172. — Machaerocereus eruca. 



2. Machaerocereus gummosus (Engelmann). 



Cereus gummosus Engelmann in Brandegee, Proc. Calif. Acad. II. 2: 162 

 Cereus cumengei Weber, Bull. Mus. Hist. Nat. Paris 1: 317. 1895. 

 Cereus flexuosus Engelmann in Coulter, Contr. TJ. S. Nat. Herb. 3: 411. 

 Lemaireocereus cumengei Britton and Rose, Contr. U. S. Nat. Herb. 



12:424. 1909. 

 Lemaireocereus gummosus Britton and Rose, Contr. U. S. Nat. 12: 



425. 1909. 



Erect or ascending, but usually not a meter high, or with long, 

 spreading, sometimes prostrate, branches, the whole plant sometimes 

 having a spread of 6 to 7 meters; branches 4 to 6 cm. in diameter; 

 ribs usually 8, rarely 9, low and obtuse; areoles rather large, about 

 2 cm. apart; spines stout, the radials 8 to 12, somewhat unequal, 

 about 1 cm. long; central spines 3 to 6, stout, flattened, one much 

 longer than the others and about 4 cm. long; flowers 10 to 14 cm. 

 long, the tube long and slender; inner perianth-segments 2 to 2.5 

 cm. long, purple; stamens about as long as the segments; fruit sub- 

 globose, 6 to 8 cm. in diameter, spiny; skin of fruit bright scarlet; 

 pulp purple; seeds rugose, pitted, 2.5 mm. long. 



Type locality: Lower California. 



Distribution: Lower California and adjacent islands. 



Dr. Rose, who visited Lower California in 191 1, found 

 this the most widely distributed there of all the cacti. He 

 observed it at all stations visited on the main peninsula and 

 on all the islands of the Gulf of California except Tiburon 

 and Estaban. The plant is rather diverse in its habit; it 

 often sends out long horizontal branches which take root and 

 start other colonies. In habit it much resembles Rathbunia 

 alamosensis, but is usually stouter and less gregarious. The' 



