LECT. VI.] THE STEM. BRANCHING. 271 



instances either a dry powdery, or a moist excre- 

 tion. Of the former there are three varieties, and 

 two of the latter. A stem is denominated 



a. Hoary (incanus, pruinoms), when the en- 

 tire surface is strewed over with a fine white 

 dust, which is easily rubbed off, like the bloom 

 on Grapes ; as exemplified on Dwarf shrubby 

 Orache, Atriplex portulacoides. 



b. Mealy (farinosus), when the white pow- 

 der is less minute, or is mealy ; as in Bird's- 

 eye Primrose, Prinmlafarinosa. 



c. Glaucous (glaucus), when the dust or bloom 

 is of a bluish green, or sea-green colour ; as in 

 the Palma Christi, (the castor oil plant,) Rici- 

 nus officinalis, &c. 



d. Viscid (viscidus), when it is covered with 

 a clammy resinous exudation; as in clammy 

 Catchfly, Silene* viscosa. 



e. Glutinous (glutinosus), when the exuda- 

 tion is adhesive ; but, instead of being resinous, 

 it is gummy or soluble in water ; as in clammy 

 Primrose, Primula glutinosa. 



Besides being covered with the appendages we 

 have just examined, the surfaces of stems pre- 

 sent inequalities from a variety of causes ; and as 

 these are fixed and always appear in every indi- 

 vidual of a species, they are taken advantage of 

 in the formation of specific distinctions ; and, 

 therefore, require to be pointed out. A stem is 

 termed 



