FLORAL FORMS AND THEIR RELATIONS TO INSECTS 345 



semble the latter in possessing a double lip, the essential point of difference 

 being that their lower lips approximate to the upper, so as to close the orifice 

 of the tube or throat. In the Toadflax (fig. 429) this arrangement shuts out 

 flies and beetles, which lack the requisite strength to force an entrance, 

 while the length of the nectar-storing spur excludes short-lipped bees, which 

 are not so incapable of breaking in. Thus the flowers become exclusively 

 adapted for the long-tongued species, by which, indeed, they are diligently 

 visited. The Toadflax, it may be noted in passing, is one of those flowers 

 which, though normally irregular, will sometimes become regular by 

 producing in all 

 their petals or 

 sepals the very fea- 

 ture which is the 

 cause of their ir- 

 regularity. In the 

 flower in question, 

 the peculiarity is 

 that each of the 

 five petals, by vir- 

 tue of this excess 

 of irregularity, pro- 

 duces a spur, while 

 the upper part of 

 the flower loses its 

 personate character 

 and becomes regu- 

 lar. The wonder 

 excited in the mind 

 of the great Linnaeus 

 by this phenomenon 

 led him to apply to 

 it the name pdoria, 

 from the Greek word 

 peldron, a monster. 

 Of course, in a 



normally and regularly spurred corolla, like the Columbine (Aquilegia, 

 vidgaris, fig. 427), the term " peloria " would not be applicable. 



The arrangement in the personate corolla of the Snapdragon is similar 

 to that of Toadflax, though not identical. Here, as there is no spur to 

 keep off smaller bee-intruders, the entrance is more firmly closed, and it 

 is only when the flower is old and beginning to wither that it opens 

 its door to such visitors. The flower is, indeed (to quote Lord Avebury), 

 ".a strong box of which the humble-bee only has the key/' This guard- 

 ing of the entrance is a necessary precaution, for if flies and small 



Photo by} [E. Step. 



FIG. 424. SEASIDE CONVOLVULUS (Convolvulus soldanella), 



With funnel-shaped pink flowers. The leaves are small, heart-shaped or kidney- 

 shaped, and the stem rarely twines. 



