178 



to make strong carbon rubbings. In such cases the Hues can 

 readily be strengthened by using a pencil. For purposes of 

 illustration leaves may be outlined by this carbon paper method, 

 the lines inked, and the drawing afterward cleaned up with a 

 soft eraser, with the absolute certainty that the drawing will 

 represent the true outline of the leaf and the details of its venation 

 down to the ultimate reticulation. 



Fig. 2. Platanus orientalis L. 



In herbarium practice I have found these carbon rubbings or 

 impressions to be of the very greatest utility. To illustrate their 

 value I will merely cite a few representative cases. In January, 

 1908, I made a carbon impression of a single typical leaf of 

 Bauhinia warburgii Perk., the type of which is preserved in the 

 Berlin herbarium. This species did not appear in our Philippine 

 collections until the year 1912 or 1913, yet when it did appear 

 I was enabled at once to identify the specimen, merely by direct 

 comparison with my carbon rubbing of a single leaf from the 

 type, and a very brief examination of the printed description. 



