4 
which the Sierra del Rosario are a part, forms a backbone through 
the province from northeast to southwest, and somewhat north 
of the central axis. ‘The rock is recent limestone, containing 
innumerable caves, and weathered to a surface which the native 
fittingly call diente de perro. It is only when one tries to ¢ limb 
Fic, 3. Laguna near Pinar del Rio, Cuba, showing the water-hyacinth 
(Piaropus crassipes), which here grows as a wee 
— 
the slopes that he realizes how truly descriptive is the name. 
Sierra. To negotiate these mountains on horseback was abso- 
lutely impossible, for not only were their approximately horizon- 
tal surfaces honeycombed and serrate, but in most instances the 
slopes were perpendicular to a height of 700-800 feet, usually 
with a young, rocky talus on one side only. Isolated crags 
occurred here and there, with tempting plants quite inaccessible. 
However, with the assistance of a practico with his machete, we 
made our way to the summits of some of the higher peaks, secur- 
ing many photographs and a large number of specimens. Here 
