86 



STRUCTURAL BOTANY. 



sides, as in the Cherry ; while the Involute has both its edges 

 rolled inward, as in Apple, Violet ; and Revolute has both mar- 

 gins rolled outward and back- 

 ward, as in the Dock, Willow, 

 Rosemary. 



Vernation, 283, of Birch leaf; 284, of Lilac (imbricate); 285, Cherry leaves (convolute); 286, Deck bud 

 (revolute); 287, Balm of Gilead (involute). 



257. The general vernation is loosely distinguished in desci'ip- 

 tive botany as valvate (edges meeting), and imbricate (edges 

 overlapping), terms to be noticed hereafter. The valvate more 

 often occurs in plants with opposite leaves. 



258. Imbricate vernation is Equitant (riding astraddle), 

 when conduplieate leaves alternately embrace the outer one 

 the next inner by its unfolded margins, as in the Privet and 

 Iris (282). It is Obvolute when it is half-equitant ; that is, the 

 outer leaf embraces only one of the margins of the inner, as in 

 the Sage (281). Again, it is Triquitrous where the bud is trian- 

 gular in section and the leaves equitant at each angle, as in the 

 Sedges (280). 



259. The principle of bud- 

 ding. Each leaf-bud may be 

 regarded as a distinct individ- 

 ual, capable of vegetating either 

 in its native position, or when 

 removed to another, as is exten- 

 sively practised in the impor- 

 tant operation of budding. 



260. Bulblets. In the Tiger-lily, Cicuta 

 bulbifera, and Aspidium bulbiferum, the 

 axillary buds spontaneously detach them- 

 selves, fall to the ground, and become 



new plants. These remarkable little bodies are called bidblets. 



Review. -244. Two kinds of buds. 245. Define the leaf-bud. Show the leafy nature of 

 the scales by fig. 273. The coating of bnds. 247. Buds classed as to position. Location 

 Of the axillary buds. Two kinds. When do the axillary become terminal ? 248. What 



288, Vernation of 

 Sycamore bud. 



inn the proces 

 of "budding." 



