PAN DE AZUCAR 89 



When dry, these spicules are scattered into the air 

 by any disturbance of the vine and falling upon the 

 skin produce an irritation which drives one almost 

 frantic. 



Climbing higher up the talus of limestone blocks 1 

 the area of densest vegetation is soon passed, and 

 among many species of large smooth bark trees, 

 all more or less bound in lianes, a number of long 

 slender-stemmed palms are met, the Gaussia 

 princeps, with bottle-shaped base. There are 

 usually a few royals and several species of Thrinax 

 with fan-shaped leaves. At an elevation of about 

 one hundred feet the top of the talus is reached, 

 and there begins the perpendicular paredon or wall 

 which rises anywhere from twenty to several 

 hundred feet. Its face may be a solid smooth 

 expanse of white rock offering no foothold what- 

 ever for vegetation, or it may present interruptions 

 in its even surface furnishing narrow shelves where 

 vegetation can find lodgment. From such situa- 

 tions exceedingly narrow-stemmed palms (Euterpe 

 mancele) rise to great height, and many cacti 

 and agave plants cling to their insecure perches. 

 Of the numerous cacti the most prominent is the 

 climbing Cereus pitajaya whose rounded small 



