344 



iNDt;x. 



Fasciation, 51, 85 ; of petioles of pear, 

 (fig. 26) 94 



Fertilisation, cross- (see s.t.) ; and 

 origin of species, 329 ; by pollen- 

 tube (see S.T.); varieties of, 311; 

 self- (see s.v.) 



Fibro-Tascular cord, as a fondamental 

 unit, 300, 308, 309. See Cord. 



Flora, of Dorrefjeld, and self-fertilisa- 

 tion, 259 ; of Galapagos Islands, 

 270 ; of Greenland, 270 



Floral symmetry, correlation with 

 phyllotaxis, 14; explained, 4, 5; 

 variations in, 12 



Floral whorls, development of, order 

 of, 191; emergence of, 184; sym- 

 metrical decrease and increase in, 

 18 ; unsymmetrical, 20. See Whorls. 



Flowers, conspicuous, development of 

 parts of, 191; degeneracy in, 251 ; 

 inconspicuous, origin of, 251 ; origin 

 of, 337 ; typical, structure of, (Hg. 

 1)3 



Forces, effects of mechanical, etc. 

 See Mechanical forces. 



Forms, of floral organs, 101, seqq. ; 

 dimorphic, of stamens, (Kg. 37) 

 121 ; principle of, 5 ; transitional, 

 118, seqq. 



Fnnicle, bulb arising from, 310 ; as 

 origin of ovule, 303 



6 



Galls, analogous to tumonrs, 144 ; 



due to irritation, 144; hairs of, 



138 

 Garidella, arrangement and nnmber 



of parts in, (iig. 4) 21 

 Glands and rudimentary organs, 283. 



See Nectaries. 

 Growth of organs, continuous daring 



flowering period, 122 ; correlation 



of, 112, 333 

 Guides, degeneracy of, in self-fertil- 

 ised flowers, 253 ; origin of, 178 



Gymnospei-ms, and the origin of 

 flowers, 337 



Gynandrous, 82 ; Arisiolochia, (6g. 

 21)83 



Oynodifficiam, causes of, 221, seqq. ; 

 and climate, 221 ; explained, 220 ; 

 origin of, 222, seqq. ; and soil, 221 



Qynoecium, degeneracy of, 278; ex- 

 plained, 4 ; unsymmetrical decrease 

 in, 20. See Carpels and Pistil. 



Gynomonoecism, examples of, 226 ; 

 explained, 220 



H 



Hairs, on filaments, origin of, 136 

 (see fig. 11, 60);' in galls, 138; on 

 roots, origin of, 137; on seeds, 

 170 ; within styles, origin of, 139 ; 

 tangles and wheels, origin of, 133, 

 seqq. 



Heliotrope, stigma of, cause of ano- 

 malous, 135 



Hellebore, alteration in orientation of 

 cords, (fig. 12) 64; arrangement 

 and number of parts of floral 

 whorls (fig. 5), 22 



Hercogamy, explained, 317 ; in 

 Orchids, 314; relative character 

 of, 319 



Hei-maphroditism, origin of, Mr. 

 Darwin's theory of, and observa- 

 tions on, 389 



Heterogamy, explained, 198 ; and 

 sexuality, 243 



Heteromorphic flowers explained, 

 203 



Heterostylism, explained, 203 ; and 

 diclinism, 228 ; and discism, 218 

 and degrees of fertility, 204, seqq. 

 origin of, 213 ; and sexuality, 244 

 structure of stigmas in, 216; un 

 stable, in stamens of Narcissus 

 cemutts, (fig. 37) 121 



Homogamy, explained, 198 ; and 

 anemophily, 269 ; fluctuating con- 

 ditions about, 201 



Homology, of appendages and axis, 



