14 INTRODUCTION. 



The faces of the stem are often furnished with many nearly- 

 sessile glands in some of those species which usually have 

 neither setse nor aciculi. Some stems are quite hairless; 

 but others are more or less thickly covered with hairs, which 

 are either solitary and patent, or two or three spring from 

 the same spot and diverge so as, if numerous, to interlace 

 with those of the neighbouring clusters. In some cases there 

 is more or less fine down, formed of clustered but very small 

 hairs spreading close to the surface of the stem; this is called 



felt^ tomentum^ or stellate-puhescence. The stem of a few spe- 

 cies is covered with a kind of bloom (is pruinose), especially 

 when young. The faces of the stem in the groups called 



. Suherecti, Rhamnifolii and Villicaules, are usually marked 

 with parallel longitudinal lines and have a dull appearance; 

 but a few plants (R. Linclleianus for example) have shining 

 faces to their stems. 



The leaves are either innnate with seven leaflets, of 

 which four spring from the same spot in opposite pairs, but 

 the upper three (also seated at one spot) are separated from 

 them by a considerable space; or, the upper three consist of 

 an opposite pair similarly separated from the lower fovir, but 

 the terminal leaflet is again raised above them by a short 

 stalk ; both of these combinations are called septenaie-innnaie 

 leaves: or, (in R. Idceus) five leaflets are arranged in an 

 ini2)a7d-pinnate manner: or, the leaf consists of three or five 

 leaflets, all springing from the same jDlace, of which the 

 lower are stalked or sessile, but the terminal is always 

 stalked ; these are the quinate leaves : or, the two lower are 



it (in describing those plants) to the longish gland-tijyped hairs. Some 

 confusion is caused by this latter use of the term, but, in the want of a 

 special name for those organs, it is probably better to retain its use than 

 to employ the circumlocution of gland-tipped hairs; for descriptions are 

 thereby much shortened and facilitated. 



