136 POLEMONIACEJE) BORAGINACE&. [CHAP. 



visited by butterflies, though it contains no honey, 

 at least neither Sprengel nor M tiller could find any. 

 Menyanthes and Limnanthemum (Kuhn, " Bot. Zeit," 

 1867) are said to be dimorphous. 



POLEMONIACE^E. 



This family is represented in England by one species, 

 Polemonium cceruleum^ and even this is a doubtful native. 

 It has been shown by Axell to be proterandrous. 



BORAGINACE^:. 



This order is easily distinguished from all others, 

 except the Labiatae, by the four seed-like nuts ; 

 from the Labiatae by the form of the flowers, and 

 by the leaves being alternate. It contains eleven 

 British genera, viz., Echium, Pulmonaria (Fig. 96), 

 Mertensia, Lithospermum, Myosotis, Anchusa, Ly- 

 copsis, Symphytum, Borago (Fig. 95), Asperugo, and 

 Cynoglossum. 



In consequence of its conspicuousness, and the 

 easy accessibility of its honey, Echium vulgare is 

 visited by a great variety of insects. The flower is 

 tubular, contracting towards the base, so that insects 

 are naturally conducted to the honey. The stamens 

 are five in number ; one remains in the tube of the 

 flower, while the other four project, and form a con- 

 venient alighting stage for insects, which can thus 

 hardly fail to dust their undersides with pollen. 



Echium is proterandrous ; when the flower opens 

 the anthers are already ripe ; the pistil, on the other 

 hand, is still quite short and immature, scarcely 

 reaching to the mouth of the tube. Gradually, how- 

 ever, it extends until it reaches 10 mm. beyond 



