xx i; CONTENTS. 



CHAPTER III. 



HETEEOSTYLED DIMORPHIC PLANTS continued. 



Linum grandiflorum, long-styled form utterly sterile with own- 

 form pollen Linura perenne, torsion of the pistils in the 

 long-styled formal one Homostyled species of Liuum Pul- 

 monaria officinalis, singular difference in self -fertility between 

 the English and German long-styled plants Pulinonaria 

 angustifolia shown to be a distinct species, long-styled form 

 completely self-sterile Polygon um fagopyrum Various other 

 heterostyled genera Rubiaceae Mitchella repens, fertility of 

 the flowers in pairs Houstonia Faramea, remarkable differ- 

 ence in the pollen-grains of the two forms ; torsion of the 

 stamens in the short-styled form alone ; development not as 

 yet perfect The heterostyled structure in the several Rubi- 

 aceous genera not due to descent in common . Page 81-136 



CHAPTER IV. 



HETEEOSTYLED TEIMORPHIC PLANTS. 



Lythrum salicaria Description of the three forms Their power 

 and complex manner of fertilising one another Eighteen dif- 

 ferent unions possible Mid-styled form eminently feminine 

 in nature Lythrum Graefferi likewise trimorphic L. thymi- 

 folia dimorphic L. hyssopifolia homostyled Nesaea verti- 

 cillata trimorphic Lagerstrcemia, nature doubtful Oxalis, 

 trimorphic species of 0. Valdiviana 0. Regnelli, the illegiti- 

 mate unions quite barren 0. speciosa 0. sensitiva Homo- 

 styled species of Oxalis Pontederia, the one monocotyledonous 

 genus known to include heterostyled species . . 137-187 



CHAPTER V. 



ILLEGITIMATE OFFSPRING OF HETEEOSTYLED PLANTS. 



Illegitimate offspring from all three forms of Lythrum salicaria 

 Their dwarfed stature and sterility, some utterly barren, some 



