152 FOKMS OF HAIES. [BOOK i. 



envelopes the seeds, and is wrought into linen ; in the Cow- 

 hage (Mucuna urens and pruriens), it is they which produce 

 the itching. In Ferns they are long, entangled, strangulated 

 filaments. They vary extremely in length, density, rigidity, 

 and other particulars ; on which account they have received 

 the following names : 



Down or Pubescence (pubes, adj. pubescens), when they form 



a short soft stratum, which only partially covers the 



cuticle, as in Geranium molle. 

 Hairiness (hirsuties, adj. hirsutus], when they are rather longer 



and more rigid, as in Galeopsis Tetrahit. 

 Pilosity (adj. pitosus), when they are long, soft, and erect, as 



in Daucus Carota. 

 Villosity (adj. villosus), when they are very long, very soft, 



erect, and straight, as in Epilohium hirsutum. Crini 



(adj. crinitus) are this variety in excess. 

 Velvet (velumen, adj.velutinus), when they are short, very dense 



and soft, but rather rigid, and forming a surface like 



velvet, as in many Lasiandras. 

 Tomentum (adj. tomentosus), when they are entangled, and 



close pressed to the stem, as in Geranium rotundifolium. 

 Cilice (adj. ciliatus), when long, and forming a fringe to the 



margin, like an eyelash, as in Sempervivum tectorum. 

 Bristles (setae, adj. setosus), when short and stiff, as on the 



stems of Echium. 

 Stings (stimuli, adj. stimulans ; pili subulati of De Candolle), 



when stiff and pungent, giving out an acrid juice if 



touched, as in the Nettle. 

 Glandular hairs (pili capitati), when they are tipped with a 



glandular exudation, as in Primula sinensis. These 



must not be confounded with stalked glands. 

 Hooks (hamij unci, rostella], when curved back at the point, 



as in the nuts of Myosotis Lappula. 

 Barbs (glochis, adj. glochidatus] , if forked at the apex, both 



divisions of the fork being hooked, as in the nuts of the 



same plant. 



Hairs also give the following names to the surface of any 

 thing : 



