THE HIGHER DICOTYLEDONS. 



355 



Fig. 146. Floral Diagram of 

 Foxglove. 



below than above? Note the two lobes of the upper lip 

 (=2 petals) and the less distinct lobing of the longer lower 

 lip ( 3 petals). 



If you watch humble-bees visiting 

 the flower, you should be able to 

 answer the following questions. 

 What are the uses of (1) the droop- 

 ing position of the flower, (2) the 

 curious " eye-spots " on the corolla, 

 (3) the hairs inside the corolla? 

 Examine flowers of different ages ; 

 the anthers of the upper pair of 

 stamens shed their pollen before 

 those of the lower pair, then the 

 stigma-lobes separate and are ready 

 to receive pollen; how does this 

 sequence of events promote cross- 

 pollination? Note how the two 

 anther-lobes diverge when the anther ripens. Cut across the 

 ovary and note the two chambers, with numerous ovules on 

 the axile placenta, which resembles a dumb-bell in cross- 

 section (Fig. 146). 



The egg-shaped capsule opens by splitting on each side ; 

 the partition splits into two layers, and at the same time 

 separates from the placenta, so that the two valves are formed 

 and the numerous small seeds are left on the placenta and 

 are gradually shaken off when the wind rocks the plant 

 (censer-mechanism). Note that the upper valve of the cap- 

 sule splits down the middle; sketch the ripe capsule before 

 and after opening. 



359. Speedwell (Veronica). There are 16 British species 

 of Veronica, of which 10 are common and widely distributed. 

 In certain respects they all agree : the leaves, or only the 

 upper ones, are opposite ; the flowers small and blue, with 

 4-lobed calyx and corolla, the corolla-tube being very short 

 and the lobes flat; stamens 2, projecting from the corolla 

 along with the style which ends in a small stigma. 



Germander Speedwell or "Bird's-eye" (V. chamaedrys), 

 one of the commonest species and earliest to flower (April to 

 September, but chiefly in May and June) has rather large 



