124 LETTER VIII. 



in a word, study a Pea-pod, and you will know what 

 a legume is. You must not expect, however, that it 

 will alw^ays be exactly like a Pea-pod ; on the con- 

 trary, it is longer or shorter, larger or smaller, harder, 

 thinner, or diiFerently coloured, contains more or 

 fewer seeds ; or, in short, may vary in many ways : 

 but it will always be formed upon the same plan. 

 This is what you are to take as the character which 

 holds toofether all the subdivisions of the Pea tribe. 



The most striking feature in these plants, next to 

 the legume, is the singular arrangement of the petals, 

 which gives to a very large proportion of the whole 

 natural order the name of Papilionaceous, or Butterfly- 

 flowered. By this title, we distinguish the first divi- 

 sion of the Pea tribe ; as an example of which a 

 common Pea flower would answer the purpose. I 

 however, send you a sprig of the narrow-leaved 

 Restharrow (Ononis angustifolia, Plate VIII. 2.). 

 It has leaves the veins of which are at first sight 

 ribbed rather than netted ; you Avill, however, find, 

 that the netted structure is what they really possess ; 

 at their base is a pair of stipules as in the Roses and 

 their allies. The calyx is formed of five sepals, that 

 unite in a short tube {figs. 2. & S. a.). The corolla 

 consists of five petals, one of which is larger, and 

 stands at the back of all the others, wrapping them 

 up before the flower expands {figs. 2. & 3. i.) ; this is 

 the standard, or vexillum. In front of the standard 

 are two smaller petals {figs. 2. & 3. c), which are 

 placed nearly parallel with each other, converging a 

 little at the point ; they are the ivings, or ala?, and 



