346 



INDEX. 



Obdiplostemony, 188 ; cause of, 190 ; 

 origin of, 150 



Opposite and verticillate leaves, 9 ; 

 as origin of alternate, 11 



Orchids, adhesive roots of, (fig. 42) 

 137 ; conducting tissue of, 165 ; de- 

 generacy in, 172, 280, 319 ; effect 

 of irritations on, mechanical, 114, 

 of larvae, 171, physiological, of 

 pollen-tubes, 165, seqq. ; hyper- 

 trophy in, 87 ; monstrous, 87 ; self- 

 fertilising, 253, 318 



Order of development of floral whorls, 

 relative only, 195 



Organs, floral, slow development of, 

 122 ; rudimentary, 283 



Origin of species, fertilisation and, 

 329 ; by natural selection, 333 ; by 

 response of protoplasm to environ- 

 ment, 3, 50, 51, 84, seqq., 88, 103, 

 seqq., 112, soqq., 116, seqq., 126, 

 133, seqq. 



Ovary, arrest of, 169; growth from 

 irritation of larva?, 171, from me- 

 chanical irritations, 114 ; from 

 pollen-tube, 170, seqq. 



Ovules, basilai-, interpretation of, 74 ; 

 of Beta (fig. 16), 73 ; emergence 

 of, 195; homology of, 303, seqq.; 

 foliaceous, (fig. 85) 305; meta- 

 morphoses of, 305, seqq. ; of Or- 

 chids, 166, seqq., 281 ; order of de- 

 velopment, interpretation of, 196 ; 

 origin of, 303, seqq. ; phyllody of, 

 302, (fig. 85) 305, (fig. 86) 306 



Pansy, stigma and style of, (fig. 54) 



255 ; self-fertilising forms, (fig. 55) 



257 



Pathfinders and colours, 178 



Pear, cause of obliquity at base of, 



(fig. 38) 124 ; interpretation of re- 



ceptacular tube of, 86, (fig. 22, a) 

 90, (fig. 26) 94 ; effect of tension 

 and weight of, upon form of, 124 



Pedicel, origin from peduncle in 

 Erodium, 309 



Pelargonium, anatomv of floral recep- 

 tacle, (fig. 13) 65-67 



Peloria, 128, seqq. ; causes of, 130 ; 

 and generic characters, 132 ; he- 

 reditary, 131 ; and hypertrophy, 

 131; induced by Tingidce, 130 



Perianth, excrescence on, (fig. 87) 

 306 ; form of, 101 



Perigynous condition, 78 



Petals, adhesion of, 78, seqq. ; co- 

 hesion of, 56, seqq. ; colours of, 

 174, seqq. ; 253, 270, {see Colours) ; 

 irritability of, 158, (fig. 47) 160, 

 (fig. 49) 162. See Corolla. 



Phyllody, of carpels, 302 ; of floral 

 whorls, 301, seqq. ; of ovules, 302. 

 See Ovule. 



Phyllotaxis, and aestivation, (fig. 3) 

 15 ; and arrangement, 39, seqq. ; 

 and number, 9, seqq. ; and origin 

 of flowers, 339 



Phyteuma, cohesions of, (fig. 9) 50 



Pistil, carpels, number of, 4, 7, seqq. : 

 superposition of, 46, 47, in (7am- 

 panulacea;, 44 ; degeneracy in, 278 ; 

 development of, rate of, 192 ; fibro- 

 vascular cords of, (figs. 12, 13, 14, 

 16) 64, 65, 68, 71, 73 ; metamor- 

 phoses of, 295, seqq. ; movements 

 of, 162 ; rationale of superposition 

 in, 46, 47 ; syncarpous, 62, seqq. 

 See Carpel, Gynoecium, Ovary, Re- 

 ceptacular Tube. 



Pitcher of Nepenthes, origin of, 146, 

 307 



Placenta, axile, 62 ; as a carpophore, 

 72; cords of, 64-77; free-central, 

 72, 76, (fig. 19) 77 ; hypertrophy 

 of, 307 ; parietal, of Orchids, a 

 sign of degeneracy, 281 



Pollen, of anemophilous flowers, 267 ; 

 of cleistogamous flowers, 258, 

 seqq. ; degeneracy of, 273, 276 ; of 

 Orchids, 173 ; in ovules, 296 ; quan- 



