188 THE REPRODUCTIVE ORGANS 



flower, and the plant grows wild only where humble-bees 

 are found. It has five blue sepals, the posterior one forming 

 a large hood which protects the anthers and nectaries. 

 The two posterior petals are modified to form long, clawed 

 nectaries or honey-leaves () and the other petals are 

 usually absent. The stamens are indefinite and they ripen 

 before the stigmas (i. e. they are proterandrous) . 



The Larkspur (Fig. 130, 3, 4, 5) has five sepals and two 

 spurred petals ; the posterior sepal is prolonged into a 

 membraneous spur which encloses the honey-secreting spurs 

 of the two posterior petals. The flower of the Columbine 

 is regular, while those of Monkshood and Larkspur are 

 irregular. 



Sweet-Pea, Scarlet-Runner, and Gorse. The Sweet-Pea 

 (Fig. 131) is a complex bee-flower. Its calyx has five 

 united sepals, two above and three below. Its corolla has 

 five petals curiously shaped and known by distinctive 

 names (Fig. 131, 2). The large posterior petal is the 

 standard (s), the two lateral ones are the alae or wings (a), 

 and the two anterior ones, which are slightly joined, form 

 together the carina or keel (k). Note carefully how these 

 are related to one another, especially at the base, observing 

 that depressions in the wings correspond to bulges in the 

 keel. Enclosed in the keel are ten stamens, nine of them 

 being united by their filaments to form a stamen-trough 

 around the pistil, the posterior one lying free over the slit 

 (Fig. 131, 3). When the stamens are united by their 

 filaments into two sets they are said to be diadelphous. 

 The filaments and style are bent upwards at the end of the 

 keel. Honey is secreted by the bases of the stamens, and 

 collects in and is protected by the stamen-trough (s.tr). 



A clever insect like the bee is required to open the flower 

 and obtain the honey. It uses the wing-petals as an 

 alighting stage ; but these being articulated with the keel, 

 both are depressed by the weight of its body. When the 



