Chap. VI. ON HETEEOSTTLED PLANTS. 271 



We see in these two tables that the offspring from 

 a form illegitimately fertilised with pollen from 

 another plant of the same form belong, with a few 

 exceptions, to the same form as their parents. For 

 instance, out of 162 seedlings from long-styled plants 

 of Primula verts fertilised during five generations in 

 this manner, 156 were long-styled and only 6 short- 

 styled. Of 69 seedlings from P. vulgaris similarly 

 raised all were long-styled. So it was with 56 seedlings 

 from the long-styled form of the trimorphic Lythrvm 

 salicaria, and with numerous seedlings from the long- 

 styled form of Oxalis rosea. The offspring from the 

 short-styled forms of dimorphic plants, and from both 

 the mid-styled and short-styled forms of trimorphic 

 plants, fertilised with their own-form pollen, likewise 

 tend to belong to the same form as their parents, but 

 not in so marked a manner as in the case of the long- 

 styled form. There are three cases in Table 37, in 

 which a form of Lythrum was fertilised illegitimately 

 with pollen from another form ; and in two of these 

 cases all the offspring belonged to the same two forms 

 as their parents, whilst in the third case they belonged 

 to all three forms. 



The cases hitherto given relate to illegitimate unions, 

 but Hildebrand, Fritz Miiller, and myself found that 

 a very large proportion, or all of the offspring, from a 

 legitimate union between any two forms of the tri- 

 morphic species of Oxalis belonged to the same two 

 forms. A similar rule therefore holds good with unions 

 which are fully fertile, as with those of an illegiti- 

 mate nature which are more or less sterile. When 

 some of the seedlings from a heterostyled plant belong 

 to a different form from that of its parents, Hildebrand 

 accounts for the fact by reversion. For instance, the 

 long-styled parent-plant of Primula veris, from which 



