344 



HUTCHINSON'S POPULAR BOTANY 





to relieve the strain upon that part of 

 the bell where the weight of the humble- 

 bee presses most. 



We find ourselves among flowers of 

 more intricate construction when we 

 come to speak of labiate or lipped 

 corollas. The White Dead-nettle 

 (Lamium album}, one of the commonest 

 of our weeds, is the flower chosen for 

 illustration (fig. 425). The corolla is 

 decidedly irregular, and on a cursory 

 examination it is not easy to distin- 

 guish from one another the five coher- 

 ing petals which compose it; though 

 by bearing in mind the simple rule 

 that petals should alternate with sepals, 

 the difficulty will vanish. Guided by 

 this rule it will be found that the 

 lower lip or cleft piece in front is one 

 petal, that the pointed and inconspicuous 

 FIG. 421,-MossY PINK (Phlox subulata), appendages on either side the corolla- 



With salver-shaped corollas. ,, ,. , 



tube are the rudiments ot two more, 



and that the remaining pair form the overshadowing hood or upper lip 

 of the flower. "We can estimate by direct observation," says Hermann 

 Miiller, "how perfect the adaptation of this flower is to bees' [humble- 

 or other large bees'] visits. The bee alights on the under lip, and in 

 doing so thrusts its head between the broad lateral lobes of the mouth, 

 clings with its fore feet to the base of the under lip, and with its inid- 

 and hind-feet to the two lobes of the under lip; then if its proboscis is 

 not less than ten millimetres [about two-fifths of an inch] long, it can at 

 once reach the base of the flower. While sucking, the thorax, and in 

 the case of small workers the base 

 of the abdomen also, fills up the 

 space between the upper and lower 

 lips, and the vaulted upper lip fits 

 the bee's back, which is pressed 

 against the stigma and the open 

 face of the anther." 



Personate or mask-like corollas, 

 of which the Toadflax (Linaria) 

 and Snapdragon (Antirrhinum^) 

 offer convenient examples, are even 

 more elaborate in their construction 

 than the labiate form. They re- 



FIG. 422. WHORTLE- 

 BERRY (Vaccinium). 

 TJrceolate corolla. 



FIG. 423. GRAPE- 

 VINE (Vitis). 

 ilitMBform corolla. 



