EARLY SUMMER FLOWERS 171 



These tubercles on the roots of this plant and its relatives are 

 inhabited by Bacteria, which assist the plant to obtain the 

 nitrogen it requires as food. At the upper end of the root we 

 find a number of short, stout branches, from which thinner pro- 

 strate shoots in turn arise. It is the latter only that are obtained 

 when a plant is pulled and not dug up, and, since they extend 

 horizontally for some distance before they appear above the 

 soil, it is easy to be misled into thinking that the whole plant 

 has been obtained. 



The underground parts of these shoots are whitish, and bear 

 only small scale leaves at the nodes. On passing farther up 

 the shoot the leaves gradually increase in size until the ordinary 

 foliage-leaves are reached. The foliage-shoots are more or less 

 erect. On them the leaves, which are exposed to the light, are 

 larger. The stem is green, sometimes with a more or less intense 

 red tint on the side exposed to the light. The terminal bud 

 continues to grow and unfold new leaves, while in the axils of 

 the uppermost foliage leaves the inflorescences occur as lateral 

 branches. 



The foliage leaves are pinnate and have no true stalks. The 

 lowest pair of leaflets stands close to the insertion of the leaf on 

 the stem. Separated from them by a short stalk come the other 

 pair of leaflets and the single terminal leaflet. The leaflets of 

 the lower pair are readily mistaken for stipules, but minute 

 pointed stipules can sometimes be made out in addition to them. 



The inflorescence has a long, thin, leafless stalk, at the upper 

 end of which is a small green bract with three leaflets and a group 

 of flowers. The short stalks of the flowers all spring from the 

 same point, and the flowers bend over so as to face in the one 

 direction. A single flower requires to be examined in great 

 detail if the method of pollination is to be appreciated. What 

 might appear to be trifling details of structure have their signi- 

 ficance and use. 



The flowers (Fig. 82, i, 2) are irregular and stand in a definite 

 position, so that an upper and a lower side can be distinguished. 

 The calyx is composed of five sepals. These are united together 

 to form a tubular structure, surrounding and holding in place the 

 bases of the petals. As the free projecting tips of the sepals show, 



