Centranthus. 89 



(Plate III. fig. 112, longitudinal section of lower part of 

 corolla-tube) it is the gynsecium, in fact the ovary, that is 

 furnished with a tangle of trichomes. These reach from 

 tTie ovary to the inner side of the perianth, and exclude 

 all unbidden guests from the nectar in the space below. 

 In Yinca herbacea (Plate III. fig. 106, longitudinal sec- 

 tion of lower part of flower ; fig. 108, a single stamen ; 

 fig. 107, the style) there is a tuft Of trichomes at the top 

 of each stamen. These interlace with similar trichomes 

 on the top of the disc-shaped head of the style, and 

 with their aid stop up the coroUa-tube, giving the 

 impression of a plug of cotton-wool being stuck in the 

 mouth of the tube. One of the most curious arrange- 

 ments which have to be noticed in this section is that 

 which exists in Centranthus angustifolius and C. ruber. 

 The corolla- tube in these flowers is twelve mm. in 

 length, and hardly one mm. in diameter. It is divided 

 throughout its whole length into two compartments by 

 a membranous septum. In the upper and smaller of 

 these compartments lies the thread-like style, while the 

 inferior and somewhat wider one is prolonged at its 

 base into a saccular spur, in which nectar is secreted 

 (Plate III. fig. 97, longitudinal section of flower of 

 Centranthus ruber ; fig. 98, transverse section). This 

 lower compartment is thickly set with trichomes the 

 whole way down from its mouth to the spur; and 

 though these trichomes permit the insertion of a pro- 

 boscis, they render it quite impossible for any of the 



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