Path-pointing Bracts. 97 



the petals. Insects when they find themselves at 

 these trellises never try to penetrate them so as to get 

 to the bottom of the flower through the clefts behind, 

 but use them as bridges by which to mount on to the 

 lamina of the petals, and thence pass on to the nectar 

 through the central aperture of the flower. 



It has already been noticed in an earlier section, 

 that bracts also, when split up into a lattice of inter- 

 crossing fringes, or when covered with hair-like tri- 

 chomes, confer a similar advantage on the flowers and 

 inflorescences which they surround ; and that they 

 compel such small insects as may light on the invo- 

 lucre to follow that path which alone will make them 

 welcome visitors. Such " path-pointing " bracts are to 

 be found in plants of the most widely separated 

 species ; and I wUl merely mention here a few 

 examples taken from the most diverse families. Such 

 then is, the very beautiful involucre of Lagtecia cumi- 

 noides (Umbelliferse), and of Nigella damascena (Eanun- 

 culacese) ; such also the trellised bracts that surround 

 the blossom of Cleonia lusitanica (Labiatse), and of 

 Rhinanthus angustifoliys Grmelin (Scrophulariacese) ; 

 such again the involucre of Gentaurea pseudophrygia 

 C. A. Meyer (Compositse), of which last a drawing is 

 given in Plate I. fig. 17. 



Finally, I may remark that hair-like trichomes, when 

 found on stems and leaves, stand in most cases in no 

 idirect functional relation to the visits of animals; 



