

GENERAL PEUSrCIPLES. 



etc., are all terms used, but well enough under- 

 stood. 

 The leaf stalk has often striking peculiarities in certain 

 varieties, such as unusually lo7ig, stout, slwrt, or slender. 

 There are also glands on the leaf-stalk, close to the base, 

 and in certain cases on the leaf itself, that are chiefly taken 

 notice of in identifying varieties of the peach and necta- 

 rine ; these difier in 

 shape too, being globiir- 

 lar (as in fig. 31), reni- 

 form or hidney-sJiajped 

 (fig. 32); these little 

 glands are supposed to 

 be, and no doubt are, or- 

 gans of secretion. 



These are all interest- 

 ing items in the study of 

 the beautiful and almost 

 endless variety of forms which the difterent classes of 

 fruit trees, and even difierent varieties of the same class, 

 exhibit in their foliage. 



Fig. 31. 



Fig.Z\, a leaf of the 

 peach w-ith globular 

 glands. 



Fig. 32. 



Fig. 32, the sanie, 

 with reniform or kid- 

 ney-shaped glands. 



, Section 6. — Flowees. 



1st. Different Parts of Flowers. — Flowers are the 

 principal reproductive organs of trees, and consist of floral 

 envelopes, the calyx and corolla / and of sexual organs, 

 stamens and jpistils. 



The Calyx {A, fig. 35) is the outer covering, and is 

 usually green like the leaves. The corolla (A, fig. 33) is 

 within the calyx, and is the colored, showy part of the 

 fiower ; its divisions are called petals. 



Stainens (fig. 3-1) are the male organs of plants. They 

 are delicate, thread-like productions (^,fig. 3tt) in the cen- 

 tre of the flower, supporting on their extremities the anthers 



