24 THE LIVING CYCADS 



precipitous descent to the valley abounds in Ceratozamia 

 (Fig. 8). 



The plant seldom reaches a height of six feet, and 

 specimens three or four feet high may be regarded as 

 very large. It grows in such deeply shaded places that 

 a brand of photographic plates which gave full exposures 

 in one-fifth of a second in the Dioon edule locality required 

 three minutes to yield a similar negative of Ceratozamia. 

 The epiphytic vegetation is very rich, and there is a 

 peculiar Begonia with leaves three feet across. The 

 whole region would be worth investigating, particularly 

 the mountain slopes on the other side of the valley, 

 where two waterfalls, perhaps a thousand feet in height, 

 look like slender white ribbons at the left of Naolinco. 



