CHAP. II. GLANDS. 51 



occasionally cupulate, wlien they receive the name of glandes 

 d godet {glandulce urceolares) from some French writers. 

 Warts are the glandes cellulaires of Mirbel ; but they must not 

 be confounded with the glandes vasculaires of the same writer, 

 which are not mere excrescences of the epidermis, but modifi- 

 cations of well known organs. ( See Discus, further on. ) The 

 presence of minute warts upon the surface of a leaf gives rise 

 to a peculiar kind of roughness which is called scabrities, and 

 such a sm'face is then said to be scabrous (scaber) : this must 

 not be confounded with asperity. 



Papillce {Glandulce utriculaires of Guettard) are minute 

 transparent elevated points of the cuticle, filled with fluid, and 

 covering closely the whole surface upon which they appear. 

 In other words, they are elevated, distended bladders of the 

 cuticle. The presence of papillae upon the leaves of the ice 

 plant gives rise to the peculiar crystalline nature of its surface ; 

 they also cause the satiny appearance of the petals, upon 

 which they almost ah^ays exist in great quantities. Link re- 

 marks, that the petals of Plantago, which are destitute of pa- 

 pillae, are also without the usual satiny lustre of those organs. 

 Wlien the papillae are much elongated beyond the surface, as 

 in many stigmas, of which they form the collecting fringes, 

 they receive sometimes the name oi papules. It should be ob- 

 served, that in De Candolle's Theorie Elementaij-e, these two 

 terms are transposed, each having received the definition be- 

 longing to the other. 



Lenticular glands {Lenticelles of De Candolle ; Glandes 

 lenticulaires oi Guettard;) are brown oval spots found upon 

 the bark of many plants, especially willows : they indicate the 

 points fi-om which roots will appear if the branch be placed 

 in circumstances favourable to their production. Tliey are 

 considered by De Candolle to bear the same relation to the 

 roots that buds bear to young branches. {Premier Mem. sur 

 ks Lentic, in the Ann. des Sciences Naturelles.) It is, how- 

 ever, extremely doubtful whether they are anything more 

 than portions of the bark, either disturbed by the growth of 

 incipient roots, or disorganised by some other unknown 



power. 



E 2 



