156 



Introductory View of the 



being arranged in various ways, form the pinnate leaf, the 

 ternate leaf, the quinate, the stellate or verticillate, &c. &c. 

 Suppose a stalk to have several leaves at each side, growing 

 at regular distances, in pairs, this is a pinnate (winged) leaf 

 ( fig, 42. a) ; if the stalk terminate in a leaflet, it will be termed 

 pinnate with an odd leaflet 

 ( h). Imagine one of the lat- 

 ter leaves to have a very long 

 stalk, with similar pinnate leaves 

 set on each side of it ( c ), 

 this is a hipinnate (twice- 

 winged) leaf; these being again 

 arranged in the same manner, 

 upon a third stalk, form a tri- 

 pinnate leaf {d) ', and, in pro- 

 portion as this is repeated, the 

 leaf will become compound, de- 

 compound, superdecompound, 

 &c. &c. It frequently hap- 

 pens (as in Jig, 42. b) that the 

 leaflets towards the end of the 

 leaf are smaller than those at 

 the base, which gives the leaf 

 somewhat of a triangular ap- 

 pearance; the more conspi- 

 cuous in proportion as it is more compound. The um- 

 belliferous (umbel-bearing) plants, which compose nearly the 

 whole of the second order of the class Pentandria, have, with 

 few exceptions, pinnate leaves, more or less compound. 



The British Flora possesses only eight genera in this order, 

 that are not included in the natural family called Umbelliferae 

 or Umbellatae. Of this number are the beet (^eta), of which 

 the root is eaten in salads (it contains a great quantity of sugar, 

 which may be extracted and manufactured for use) ; the glass- 

 wort (Salsola), used in the manufacture of glass ; the elm ( C/1- 

 mus); and the gentian (Gen\\dna\ a genus remarkable for the 

 brilliant blue colour of its flowers, and the bitterness of its 

 roots. " As bitter as gentian," is a common phrase. The 

 root of a species of gentian growing on the Alps, and other 

 mountains on the Continent (G. lutea), is the bitter chiefly 

 used in medicine. 



The umbelliferous plants agree in having their flowers supe» 

 rior and pentapetaloiiSy and in producing a naked fruit of two 

 seeds slightly attached together. Many of them are so much 

 alike in their general character, as not easily to be distin- 

 guished. Hence mistakes have occurred ; the more important, 



