176 BUD-SCALES VERNATION. [BOOK i. 



inner scales, as in Lilium. The outer covering of a bulb of 

 the first kind is called the tunic. 



It has been already stated that there are certain leaf-buds, 

 developed upon stems in the air, and separating spontaneously 

 from the part that bears them, which are altogether of the 

 nature of bulbs. Such are found in Lilium tigrinum, some 

 Alliums, &c. They have been called bulbilli, propagims, 

 bacilli) &c. Care must be taken not to follow some botanists, 

 in confounding with them the seeds of certain Amaryllids, 

 which have a fleshy coat ; but which, with a vague external 

 resemblance to bulbs, have in every respect the structure of 

 genuine seeds. 



Some buds produce leaves only, others flowers only, others 

 both leaves and flowers ; the first are the usual state, the 

 second occur in the Peach, Apple, &c., the third in the Lilac 

 and Horsechesnut. These varieties are more different in 

 appearance than in reality, and arise out of the different 

 degrees of growth which the parts within the bud-scales have 

 acquired at the time of expansion of the bud, Moreover, 

 since flowers are as much made up of leaves as branches 

 themselves, as will be hereafter shown, it follows that after 

 all a flower bud is but a leaf-bud in a peculiar condition. 



The tegmenta, or scales of the bud, have received the fol- 

 lowing names, according to the part of the leaf of which they 

 appear to be a transformation ; such terms are, however, but 

 seldom employed : 



1. foliacea, when they are abortive leaves, as in Daphne 



Mezereum. 



2. petiolacea, when they are formed by the persistent base of 



the petiole, as in the Walnut Tree (Juglans regia.) 



3. stipulacea, when they arise from the union of stipules, 



which roll together and envelope the young shoot, as in 

 Carpinus, Ostrya, Magnolia, &c. 



4. fulcracea, when they are formed of petioles and stipules 



combined, as in Prunus domestica, &c. (Rich. Nouv. 



Elem. 134. ed. 3.) 



The manner in which the young leaves are arranged within 

 the leaf-bud is called foliation, or vernation. The names 

 applied to the various modifications of this will be explained 

 in Glossology ; they are of some practical importance for 



