18 INTRODUCTION. 



either racemose or corymbose, and they, as well as the pe- 

 duncles, sjDread at different angles. Characters derived from 

 them are not easily described, and therefore are of less value 

 to the student than they seem really to be in nature. The 

 rachis and peduncles, and often the whole of the flowering 

 shoot, are usually furnished with setae (even in species the 

 stems of which have no such organs), often have aciculi, 

 many hairs, and frequently a thick coat of felt. The setae 

 on these parts are sometimes shorter than the hairs (sunken), 

 and may easily be overlooked when not pointed out by their 

 peculiar coloiu\ The sepals are usually clothed similarly to 

 the peduncles; they differ considerably in shape and direc- 

 tion when accompanying the fruit. They either end in a 

 minute point, or a linear or flattened and leaf-like append- 

 age. In considering the characters derived from this ap- 

 pendage, it is its presence, not absence, that is supposed to 

 be of value. For those plants which usually possess the leaf- 

 like point, often only produce it on the calyx of the primordial 

 flower, which terminates the panicle, and even there it is not 

 always to be found. This uncertainty renders it of much less 

 use than, from its apparent value, it ought to possess. 



Arrhenius and Godron state that the petals furnish most 

 valuable characters. It unfortunately happens that they 

 have not received so much attention in England as it is pro- 

 bable that they deserve. They are sometimes very broad 

 so that their edges overlap; or may be so narrow as to be 

 quite separate from each other, and to give a star-like ap- 

 pearance to the flower : they are broad to the base, or wedge- 

 shaped ; rounded at the end, or lanceolate ; entire, or notched 

 at the end; wavy at the edges, or throughout, or plain. In 

 colour they are most frequently white, although often pink, 

 or even sometimes reddish. 



