64 



may be distinguished from spines, which are really branches, 

 i.e. continuations of the internal tissues, by the fact that they 

 are superficial structures which are easily broken off, and if 

 the bark is stripped off they often come away with it such as 

 do those of Roses and Rubus. 



A few of the terms used for describing the surface of 

 plant members have been given above and in addition to them 

 the following are in common use :- 



echinate, with sharp prickles, like a hedgehog; 

 verrucose, or tuberculate, warty, with knobby excrescen- 

 ces; 



scabrous, rough to the touch ; 

 rugose, wrinkled. 



The surface is also often provided with hairs, or wax, and 

 said to be : 



glabrous, if without hairs ; 



glabrescent, almost glabrous, with very few hairs ; 

 pubescent, with short, soft, straight hairs; if the hairs 

 are very close together and the surface feels like 

 velvet it is said to be pilose, if the hairs are very- 

 short and only just perceptible to the touch the 

 surface is puberulous ; 



hirsute, pubescent but the hairs are longer and stiffer ; 

 villous, shaggy. The hairs are long and weak and not 



matted ; 

 tomentose, densely pubescent, but the hairs are matted 



and the surface feels softer and more woolly ; 

 woolly, tomentose with long hairs, looking like wool ; 

 floccose, woolly but the hairs are easily detached, e.g. 

 those on the undersurf ace of leaves of Pyrus lanata ; 

 mealy, hairs are very short and are easily rubbed off like 

 powder, e.g. those on young leaves of Loranthus 

 pulverulentus ; 



hoary, or canescent, with a greyish-white appearance, due 

 to very minute hairs, too small to be easily distin- 

 guished ; 

 strigose, with pointed, straight, stiff hairs, lying along 



the surface ; 



silky, with closely adpressed, soft, fine hairs ; 

 hispid, rough with rigid hairs ; 

 glaucous, pale bluish green in colour, often due to a thin 



coating of wax, or so-called bloom, 

 pruinose, with a covering of wax, or bloom, e.g. 

 branches of Rubus lasiocarpus. 



