GENERAL CONSIDERATIONS 21 



that we may assume that every one knows at 

 least the most common and useful of them. 

 Special attention should be directed, how- 

 ever, to the fact that the surface of the leaf 

 whether it be smooth, rough, rugose, tomentose, 

 lanate, wooly, hairy, or of some other quality 

 is often of considerable value in identifying 

 varieties. The glands, which are often found 

 on the petioles, or leaf stalks, particularly in 

 stone fruits, are frequently of critical conse- 

 quence in description. Peach leaves may be 

 glandless, or set with orbicular or reniform 

 (kidney-shaped) glands. In describing plums, 

 the approximate number of glands at the base 

 of the leaf, or along the petiole, is to be 

 chiefly considered. 



General notes will usually accompany any full 

 description. It will be seen that most of the 

 description blanks in use offer comparatively 

 ample space for this entry. These notes may 

 cover such a wide range that it is hardly pos- 

 sible to give any general directions for mak- 

 ing them. Peculiarities of soil or location, 

 which might have influenced the specimens 

 described ; facts with regard to the storage of 

 the specimens ; notes on insect or fungus in- 

 juries ; general remarks on the value or uses 



