ROOT-SVSTIJMS OF PERENNIALS. 



63 



The other woody plants growing near Fouqiiieria were mainly Covillea 

 tiidentafa, and an occasional specimen of Parkinsonia micro phylla. 



Two specimens of Fouqiiieria were specially studied, of which one was 

 young and the other mature. The younger plant had a shoot 24 cm. high, 

 which had a central main axis and two branches 3 cm. and 15 cm. long. 

 The habit of the plant is well shown in fig. 7. 



The roots of Fouquieria splendens are coarse and brittle, and bear rela- 

 tively few branches. The tap root was large and penetrated the ground 

 S cm., where it forked, one branch extending horizontally 13 cm. and the 

 other going down 18 cm. before branching. Each of the main forks of the 

 main root ])ranched onlv two or three times. 



Fig. S.—Honzontal extension of the root-system of Fouquieria splendens from the bajada at 

 the north base of Tumamoc Hill. Dots represent position of Covillea liideniat a, which 

 occurred withm the root-area of Fouquieria, and dotted lines such roots of Covillea as 

 were found on the same horizon as the Fouquieria roots. 



Above the forking of the tap root, about 3 to 4 cm. from the surface of 

 the ground, two laterals arose, which, as far as traced, ran in a nearly hori- 

 zontal direction. One of these bore 3 branches and was over 22 cm. long. 

 At the base the laterals were less than i cm. in diameter, and, where broken 

 off, they were slightly more than i mm. in diameter. Thus the roots of 

 Fouquieria are so heavy that they may perhaps be termed fleshy. 



