194 Miss Bale, On certain outgrowths (Intumescences) 



of the leaf to appear rough, or they may be as much as a quarter 

 of an inch in length. Their shape is also variable. Some are 

 elongated and almost cylindrical, with a conical apex. Others 

 are relatively short and broad ; some are lobed or branched. 

 Frequently they are massed together on a low cushion of green 

 tissue from which they radiate outwards. 



On the stem the outgrowths are all of considerable size and 

 occur singly. On the older parts of the stem most of the out- 

 growths appear brown and shrivelled, but young and old stages 

 may occur in close proximity. 



The formation of outgrowths usually begins on or near the 

 edges of the leaves, most frequently on the upper side, but some- 

 times on the under side, or on both. In most cases, though not 

 invariably, the development of outgrowths is accompanied by a 

 curling of the leaves downwards and inwards, and sometimes also 

 by a drooping of the lamina (fig. 1). 



The outgrowths on petioles and stems are usually larger and 

 more numerous than those on the leaves. The outgrowths 

 generally shrivel and die before the leaves, and in some cases 

 there appears to be a succession of them, since the same leaf may at 

 the same time have some which are dead and others which are alive. 

 On the stem there is a regular succession of outgrowths ; new ones 

 appearing a little way below the apex and dying off lower down. 



On the green capsules there are always outgrowths which are 

 usually particularly large and numerous (fig. 3). 



In addition to these outgrowths the stems and leaves are 

 thickly covered with hairs, which even with the naked eye may 

 be seen to be of three kinds : 



(1) simple straight hairs, 



(2) three-rayed, stellate hairs, 



(3) glandular hairs. 



The two former kinds are stiff, the latter delicate. The simple 

 hairs occur all over the plant, the stellate hairs chiefly on the 

 under sides of the leaves, for the most part on the larger veins. 

 The glandular hairs, which are to be found on all parts, are most 

 numerous on the young stems and petioles. A portion of the stem 

 (fig. 2) seen under a lens, shows a number of delicate glandular 

 hairs of great length, whose heads are each enveloped in a drop of 

 secretion, often considerable in amount. Even after a piece of 

 the shoot had been kept in water in the laboratory for a fortnight, 

 these drops still retained their original size and form. Amongst 

 the glandular hairs and evidently serving them as a protection 

 are many straight stiff hairs, some of which are longer even than 

 the glandular hairs. Irregularly distributed on the surface of the 

 stem are the colourless outgrowths of irregular shape, some simple, 

 some lobed, but never in groups as they are on the leaves. 



