TEASEL 203 



tube is not wide enough for an insect to insert its head if there were 

 two stigmas. The inner surface of the stigma is covered with papillae 

 The floral bracts overtop the anthers and stigmas, and insects do not 

 touch the last with the ventral surface in creeping over the flower, but 

 with the head when inserting the proboscis. Hence it is of advantage 

 that the second stigma is rudimentary, as if both were present the 

 inner surfaces, which alone are receptive, might not be rubbed by the 

 bee in its effort to penetrate the tube. Honey is secreted in the upper 

 part of the ovary, and the corolla tube by its length helps to contain 



Photo. Flatters & Garnett 



TEASEL (Dtpsacus sylvestris, Huds.) 



and conceal it. The divisions get into each other's way, an instance in 

 which nature can afford to improve the present arrangement. 



The Teasel is visited by Bombus rupestris, B. lapidariiis, B. 

 agrorum. 



The fruits are provided with a parachute arrangement which aids 

 in wind-dispersal, in the form of persistent bracts or leaf-like organs. 



The Teasel is a sand-loving plant growing on a sand soil, but 

 requires also some proportion of humus. 



Only moths feed on it, as the Burnished Brass Plusia chrysitis, 

 Square-spot Rustic Agrotis xanthographa, Euposcilia roseana, Auti- 

 thena Gentianana. 



Dipsacus, Dioscorides, is from the Greek dipsao, I thirst, because 

 of the water collected in the base of the leaves. Teasel is from 



