Narrow Tubular Passages. 1 1 1 



juncif alius), the channel is formed by the perianth ; in 

 the other {(Enofh&ra grandiflora) by the calyx ; while in 

 JEv/phrasia longiflora, Fedia graciliflora, Crucianella 

 gilanica. Primula longiflora, Pedicularis tubiflora, As- 

 perula longiflora, and many other flowers, it is the 

 coroUa which serves the purpose, being reduced in its 

 lower part, to a long straight tube of such narrow 

 dimensions as often to be impervious to a proboscis of 

 more than 0"2 to 0'3 mm. in diameter. In all the 

 above instances, the leaves, out of which the tube is 

 ideally composed, are coherent. But in Matthiola 

 varia DC. (Plate II. fig. 63) the tubular channel is 

 formed by petals which are not coherent but merely 

 overlap, in combination with the sepals, which are stiff, 

 erect, and closely apposed ; while the small hole which 

 serves as mouth to the channel is made by the upper- 

 most petal being rolled into the shape of a funnel. 



Frequently again it is by ridge-like processes of the 

 perianth that the narrow passages are formed. In Lilium 

 martagon, for instance (Plate II. fig. 42, a whole perianth 

 leaf; fig. 43,transverse section of a perianth leaf), the nec- 

 taries run down the centre of the perianth- leaves, and are 

 each enclosed by a pair of raised borders, which incline 

 towards each other, meet, and form a very narrow canal 

 in which the nectar is completely hidden, and which is 

 only accessible to a thin proboscis. Eidge-like pro- 

 cesses are found also on the petals of Linum viscosum 

 and Linum catharticum, and of many species of Gera- 



