28 



GENERAL PRINCIPLES. 



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

 stood. 



The leaf stalk has often striking peculiarities in certain 

 varieties, such as unusually long, stout, short, 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 differ in 

 shape too, being globu- 

 lar (as in fig. 31), reni- 

 form or Sidney-shaped 

 (fig. 32); these little 

 glands are supposed to 

 be, and no doubt are, or- 

 FIO. 31. gans of secretion. FIG. 32. 



Fig. 31. a leaf of the These are all interest- Fig. 32, the same; 



reach *,th globular ing i te m 8 in the study of ^XXnds ki<1 ' 



the beautiful and almost 



endless variety of forms which the different classes of 

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

 exhibit in their foliage. 



SECTION 6. FLOWERS. 



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 pistils. 



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 

 flower ; its divisions are called petals. 



Stamens (fig. 34) are the male organs of plants. Tlicv 

 are delicate, thread-like productions (A, fig. 34) in the cen- 

 tre of the flower, supporting on their extremities the anthera 



