424 ORDER LEGUMINOS^E, OR PEA TRIBE. 



tinguislied by a singular arrangement of the petals, from which 

 they have been termed Papilionaceous plants, owing to the 

 resemblance which their flowers bear to a Butterfly at rest. Of 

 this structure, the common Pea is an excellent illustration. If 

 we examine its flower, we shall find a calyx composed of five 

 small nearly equal sepals united into a short tube. The corolla 

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

 surpasses the rest in size, standing at the back of them, and 

 over- wrapping them before the flower expands ; this is called the 

 standard or vexillum. In front of this are two small petals, 

 which stand nearly parallel with each other, converging a little 

 at the point ; these are the wings, or alee. They are carefully 

 folded over a boat-shaped curved part of the corolla, which is 

 placed in front of all the rest; this part, termed the keel, or 

 carina, is formed of two petals, which are slightly adherent at 

 their lower edge, but which are separately inserted at their 

 base. 



588. There is considerable variety, in this order, as to the 

 number and degree of adhesion of the stamens. The Papilionaceous 

 division of it may be separated into those which have their 

 stamens united, and those in which they are distinct. The former 

 group contains all the European species, such as Peas, Beans, 

 Vetches, Clover, Trefoil, &c. The stamens are usually double 

 the number of the sepals (of which there are occasionally only 

 four) ; and very commonly one of them is distinct, whilst the 

 rest are united at their edges, as is the case in the common Pea, 

 Vetch. &c. The division of the Papilionaceous Leguminosas 

 having the stamens separate, contains few but New Holland 

 species. The ovary is a tapering green hairy body, gradually 

 narrowing into a style, which ends in a minute stigma. It is 

 one-celled, and is to be regarded as consisting of but a single 

 carpel ; sometimes, however, two or even five carpels are to be 

 found in the centre of the flower. 



589. In another division of the Leguminosse, containing the 

 Senna, Logwood, Tamarind, and many other interesting species, 

 the flowers present a much nearer approach to regularity. Their 

 petals spread equally round the pistil, as in other plants ; and 



