XXXV111 



Definitions. 



50. The following minor parts of plants require to be mentioned : 

 Tendrils are either abortive petioles or peduncles, or else the 

 ends of branches or of midribs of leaves, which by holding on to and 

 coiling round any object within reach help to support the plant. 

 Thorns, or spines, and prickles are produced on many parts of plants, 

 sometimes on almost all parts of the same plant. " In all rocky and 

 parched situations plants become more spiny, the free development 

 of foliage being checked." Hooker. The term armed is frequently 

 applied to plants which have either thorns or prickles. 



51. The distinction between rough and smooth leaves or plants is 

 apparent to every one, but many terms have been found necessary 

 to describe the various sorts of hairs which clothe the leaves and 

 other parts, and their density. Generally speaking, however, these 

 terms will not be found in this book, the terms rough and smooth, 

 hairy, very hairy, etc., being considered sufficient. The term glabrous 

 is used to describe a plant, or part of it, that is free from hairs, 

 smooth implying freedom from roughness of surface of every sort ; 

 pubescent implies a slight downiness. The terms furrowed, wrinkled, 

 ribbed, warty, which describe variations from perfect smoothness, 

 explain themselves. 



52. The surface of a leaf or other organ is glaucous when it is 

 of a pale bluish-green, often with a fine bloom ; glandular, when 

 more or less covered with glands, which are small, fleshy, watery, or 

 oily bodies, sometimes mere dots. Viscid, viscous, or glutinous are 

 the terms used when a surface is covered with a sticky or clammy 

 exudation ; papillce are minute protuberances, often only visible as 

 dots. 



INDEX TO DEFINITIONS. 



(The numbers refer to the paragraphs.) 



