PROGKESSIVE METAMORPHOSES. 



287 



stimulus required to bring the extra flow to the bracts, etc., 

 being presumably the irritation induced by insect visitors. 

 The next progressive state is for bracts to assume a more 



Fig. 62. — Inflorescence of Cornus florida, 

 with four white petaloid bracts. 



Fig. 63. — Inflorescence of Darwinia, with 

 coloured petaloid bracts. 



or less staminoid character. This is rare, bat it has been 

 noticed in Abies excelsa* A substitution of anthers for 

 bracts has been seen in Melianthus major, f concerning which 

 Sig. Licopoli remarks that the flowers of chiefly the terminal 

 racemes were imperfect, the summit of the floriferous axis 

 bearing a tuft of perfect and imperfect anthers ; the petals 

 and the two carpels of the flower having been atrojDhied or 

 arrested. 



Fig. 64 represents an involucral bract of Nigella, bearing 

 an anther on one side of it; while Fig. 65, a, is that of a 

 glume of Lolium perenne with an anther. That bracts should 

 ever assume a pistilloid character is, a priori, still more 

 unlikely, as being further removed from the central organ of 

 the flower. Dr. M. T. Masters has, however, described X a 



* Teratology, p. 192. f Bull. Soc. de Bot. Fr., Rev. bib., t. xiv., p. 253. 

 X Journ. of Lin. Soc. Bat, vol. vii., p. 121. 



