

xxu 



CONTENTS. 





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m 





CHAPTER III. 



Heterostyled Dimorphic Plants — continued. 



Linum grand iflorum, long-styled form utterly sterile witty own- 

 form pollen — Linum perenne, torsion of the pistils in the 

 long-styled formal one — Homostyled species of Linum — Pul- 

 monaria officinalis, singular difference in self-fertility between 

 the English and German long-styled plants — Pulmonaria 

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

 completely self -sterile — Polygonum f agopyrum — 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. 



Heterostyled Trimorphic 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 — O. Valdiviana — O. 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 Heterostyled Plants. 



Illegitimate offspring from all three forms of Lythrum salicaria — 

 Their dwarfed stature and sterility, some utterly barren, some 



