IV 



TROPICAL FLORAS 



69 



the centre they descend into the earth and form a central 

 trunk. A French botanist, M. Emm. Liais, says of this 

 species : " If we dig we find how all these small shrubs, 

 apparently distinct, are joined together underground and 

 form the extremities of the branches of a large subterranean 

 tree which at length unite to form a single trunk. M. Renault 

 of Barbacena told me that he had dug about 20 feet deep to 

 obtain one of these trunks." The large subterranean trees 



Fig. 7. — Andira Laurifolia (Papilionacese). 



with a trunk hidden in the soil form one of the most singular 

 features of the flora of these campos of Central Brazil. 



The above facts are from Mr. Warming's book, supple- 

 mented by some details in a letter. They are certainly very 

 remarkable ; and it is difficult to understand how this mode 

 of growth has been acquired, or how the seeds get so deep 

 into the ground as to form a subterranean trunk. But 

 perhaps the cracks in the dry season explain this. 



A large part of these campos is burnt every year at the 

 end of the dry season, but as the vegetation is scanty the 



