24:0 ILLEGITIMATE OFFSPRING OF CHAP. V. 



of seed when self -fertilised. Plants of the long-styled form 

 of Pulmonaria angustifolia were, like Hildebrand's plants, 

 absolutely sterile with their own pollen, so that I could 

 never procure a single seed. On the other hand, the short- 

 styled plants of this species, differently from those of P. 

 officinalis, were fertile with their own pollen in a quite re- 

 markable degree for a heterostyled plant. From seeds care- 

 fully self-fertilised I raised 18 plants, of which 13 proved 

 short-styled and 5 long-styled. 



POLYGONUM FAGOPYRUM. 



From flowers on long-styled plants fertilised illegiti- 

 mately with pollen from the same plant, 49 seedlings were 

 raised, and these consisted of 45 long-styled and 4 short- 

 styled. From flowers on short-styled plants illegitimately 

 fertilised with pollen from the same plant 33 seedlings 

 were raised, and these consisted of 20 short-styled and 13 

 long-styled. So that the usual rule of illegitimately fer- 

 tilised long-styled plants tending much more strongly than 

 short-styled plants to reproduce their own form here holds 

 good. The illegitimate plants derived from both forms 

 flowered later than the legitimate, and were to the latter 

 in height as 69 to 100. But as these illegitimate plants 

 were descended from parents fertilised with their own 

 pollen, whilst the legitimate plants were descended from 

 parents crossed with pollen from a distinct individual, it is 

 impossible to know how much of their difference in height 

 and period of flowering is due to the illegitimate birth of 

 the one set, and how much to the other set being the pro- 

 duct of a cross between distinct plants. 



Concluding Remarks on the Illegitimate Offspring of 

 Heterostyled Trimorphic and Dimorphic Plants. 



It is remarkable how closely and in how many points 

 illegitimate unions between the two or three forms of the 

 same heterostyled species, together with their illegiti- 

 mate offspring, resemble hybrid unions between distinct 

 species together with their hybrid offspring. In both 

 cases we meet with every degree of sterility, from very 



