1C6 THE CLASS DIA1>ELPHIA. 



more sets. In the small class, now under consideration, the filaments are united together 

 into one bundle, which may consist of five stamens, as in Erodium or Stork's bill ; of 

 two stamens, as in the allied genus Geranium ; or of an indefinite number of stamens, 

 as the Malva or Mallow (Fig. 219), Althaea or Marsh Mallow, and Lavatera or Tree 

 Mallow. These four genera constitute the whole class, and are subdivided into the follow- 

 ing orders as above intimated Pentandria, Decandria, and Polyandria. None of them 

 are either edible or poisonous ; but the Malva and Althaea have been employed in 

 domestic medicine on account of the mucilaginous juices which they yield. The 

 indigenous Geranium, or Crane's bill, offers thirteen species ; but, whilst they are 

 interesting wayside herbs, they are infinitely inferior in beauty to the cultivated flowers 

 which more commonly bear that name. The whole class consists of five genera and 

 twenty-two species. 



CLASS XVII. DIADELPHIA. 



This is a class of very great importance, and is fitly associated with the Icosandria* 

 Triandria, and Tetradynamia, in supplying nutritive and pleasant food for man and 

 animals. It contains eighteen genera and seventy-four species, and, as a whole, is a 

 tolerably well-associated class of plants. It is characterised by having the filaments 

 of the anthers arranged in two sets (the second set usually consisting of but one fila- 

 ment, Fig. 221) ; and, as a rule, they are inclosed in the carina or keel of the Papillio- 

 naceous corolla (Fig. 213). It is divided into three orders, according to the number 

 of the stamens viz., Hexandria, in which there is but one genus, the Fumaria, or 

 Fumitory growing in corn-fields ; Octandria, also consisting of one genus, the Polygala 

 or Milkwort ; and, lastly, Decandria, which comprises the remaining genera. The orders 

 Hexandria and Octandria offer nothing of importance ; so that it is to the Decandria 

 that we direct our attention. In this order the ten stamens are invariably arranged in 



Fig. 350. Fig. 351. Fig. 352. 



Diadelphia Hexandria. Diadelphia Decandria. Diadelphia Octandria. 



a set of nine and an odd one, which is not readily separable from the nine by any one 

 ignorant of its separate existence. It usually lies attached to the thin edge or face of 

 the mass of filaments. The following are the chief members of this class : the Pisum 

 or Pea, Vicia or Vetch, Anthyllis or Kidney Vetch, Orobus or Bitter Vetch, Lathyrus or 

 Vetchling, Hippocrepis or Horseshoe Vetch, Astragalus or Milk Vetch, Ervum or Tare, 

 Trifolium or Clover, Lotus or Bird's Foot, Ulex or Furze, and Genista or Broom ; the 

 latter, with the Ulex, Anthyllis, and Ononis being the only instances in which all the 

 stamens are united at their base. The Pea is the only member supplying human food 

 under ordinary circumstances ; but in seasons of dearth others have been used, and 

 again may be used with great advantage. Nearly all the remaining genera are com- 

 monly used as food for animals, and a very few have medicinal properties, as the 

 Genista and the Fumaria Officinalis. None are poisonous. 



They are, for the most part, climbing plants with pinnate leaves, and the midrib 



