ANALOGY OF PLANT ORGANS. 



57 



As an abnormal instance may be montionod a scedllnj^ Begonia, 

 described and Hgured in the 'Gardeners' Chronicle ' (1877, p. 488', 

 in whicli not only the bracts bnt also the upper leaves were bril- 

 liantly coloured. 



3. Squamilonn. In this state bracts protect the flower-bud or 

 essential organs, if they be alone present ; they may be mem- 

 branous, or herbaceous and green, when they have leaf-functions 

 as well, such as the scales of the male catkins of the Cupidiferce, of 

 the female inflorescence of the hop, of the cupules of nut and 

 hornbeam. They may be woody and protective, as in the cups of 

 oak. beech, and chestnut ; lastly, they may be dry and scarious, as 

 in the Illecebracece. 



4. Bracts and bracteoles may remain almost or (j^uite rudimentary. 

 In this condition their functions have afjfiarently in most cases 

 ceased. At flrst they probably protected the young flower-bud 

 in its most primitive condition ; subsequently, they may become 

 coloured, and so pass under the second category, as the bracts 

 of the bluebell ; they may, however, remain almost microscopic in 

 size, and are then most likely functionless, as in many involucres 

 of the Uinhellijerce, and as they occur at the bases of the pedicels of 

 many racemes, etc. 



5. Bracts are often spinescent, as the involucres of thistles, of 

 Cenfaurea calcitrapa, of Bipsacua, etc. In this condition they 

 supply a means of defence, not only against browsing animals, but 

 also against "unwelcome guests" who would rob the flower of its 

 sweets without eifectiug pollenisation.^^ 



6. Bracts may be modified into ascidiform structures to secrete 

 honey. In Marcgravia Nepenthoirles] the pendulous flowers are 

 in umbellate whorls with ascidiform nectariferous bracts suspended 

 below them. These attract insects, which in their turn attract 

 insectivorous birds, which latter by brushing against the flowers 

 thus pollenate them. 



7. Spa/hiiceous, as of Aroidea, Palmacem, Amaryllidacece, etc. 

 These may take on different functions — protective, nourishing, 

 attractive, etc., according to their nature. Thus, they will protect 

 the spadix in the undeveloped state ; they may then become 

 foliaceous, as in Arum maculatum, when they sustain a tiourishing 

 office ; or petaloid, as in Anthiirium, when they are attractive ; 

 or, perhaps, in some cases, poisonous, as a preventive agency, warding 

 off herbivorous animals. 



The next progressive state to a petaloid condition is for bracts to 

 assume a more or less staminoid character. This is, however, rare. 

 The bracts of Abies exeelsa have been observed to assume the form 

 and characteristics of stamens. J A similar substitution of anthers 

 for bracts has been seen in MeliantkuH major, concerning which 

 Signor Licopoli, the observer, remarks that the flowers of (chiefly) 

 the terminal racemes were imperfect, the summit of the florifcrous 



* ' Flowers and their Unbidden Guests,' Kerner, p. 7o. 



t See Belt's 'Xaturalist in Nicaragua,' p. 129. 



X For fui'ther description see ' Teratology ' by Dr. Masters, p. 192. 



