136 BOTANY. 



(3.) Root-stocks, which are bract or scale-bearing, usually 

 weak, and subterranean. 



(4.) Tubers, which are bract or scale-bearing, short and 

 thickened, and subterranean. 



(5.) Corms, which are leaf -bearing, short and thickened, 

 and subterranean. 



(6.) Bulb-axes, which are leaf -bearing, short and conical, 

 and subterranean. 



(7.) Flower-axes, which are bract, perianth, stamen, and 

 pistil-bearing, short, and usually conical and aerial. 



(8.) Tendrils, which are degraded, slender, aerial cau- 

 lomes, nearly destitute of phyllomes. 



(9.) Thorns, which are degraded, thick, conical, aerial 

 caulomes, nearly destitute of phyllomes. 



173. Phyllome.* The phyllome is always a lateral 

 member upon a caulome. It is usually a flat expansion and 

 extension of some of the tissues of the caulome. Its most 

 common form is (1) the Leaf (foliage), which is usually large, 

 broad, and mainly made up of chlorophyll-bearing paren- 

 chyma. 



The other phyllome forms are : 



(2.) Bracts, which are smaller than leaves, generally green. 



(3.) Scales, which are usually smaller than leaves, wanting 

 in chlorophyll-bearing parenchyma, and with generally a 

 firm texture. 



(4.) Floral envelopes, which are variously modified, but 

 generally wanting in chlorophyll-bearing parenchyma, and 

 with generally a more delicate texture. 



(5.) Stamens, in which a portion of the parenchyma de- 

 velops male reproductive cells (pollen). 



(6.) Carpels, bearing or enclosing female reproductive 

 organs (ovules). 



(7.) Tendrils and Spines, which are reduced or degraded 

 forms, composed of the modified fibro-vascular bundles, and 

 a very little parenchyma ; in the first the structures are weak 

 and pliable, in the latter stout and rigid. 



The altogether special modifications of the phyllome, as in 

 pitchers and cups, will be noticed hereafter. 



* From the Greek tyvfaov, leaf. 



