OF DlMOUPlllC ANJ> TlUMOliPHIC PLANTS. 431 



styled individuals belonging to the equal-styled variety of Primula 

 veris, and thus have become self-fertile. The long-styled form of 

 Pulmonaria angustifolia is, like Dr. Hildebrand's plant, absolutely 

 sterile with its own pollen, so that I could never procure a single 

 seed. On the other hand, the short-styled form, diiferently 

 from that of P,jyfficindlis^ is fertile with its own pollen in a quite 

 remarkable degree for a dimorphic plant. From seeds carefully 

 self-fertilized I raised 18 plants, of which 13 proved to be short- 

 styled and 5 long-styled, I did not observe their power of pro- 

 ducing seed; but this, from the fertility of the first union, probably 

 would have been nearly perfect. 



Coifl*CLrsIONS IK EEOAUD TO THE ILLEGITIMATE OFFSPUma OP 



TlilMOUPllIC AKD DrMOEPHIC Plais'ts. 



It is remarkable in how many points and how closely illegiti- 

 mate unions between the two or three forms of the same species, 

 together with their illegitimate offspring, resemble hybrid unions 

 between distinct species together with their hybrid offspring. In 

 both cases we meet with every degree of sterility, from very slightly 

 lessened fertility to absolute barrenness, when not even a single 

 seed-capsule is produced. In both cases the facility of effecting 

 the first union is much influenced by the conditions to which the 

 plants are exposed *. Both with hybrids and illegitimate plants 

 the innate degree of sterility is highly variable in plants raised from 



the same mother plant. In both cases the male organs are more 

 plainly affected than the female ; and Ave often find contabescent 

 anthers enclosing shrivelled and utterly powerless pollen-grains. 

 The more sterile hybrids, as Max Wichura has well shown, are 

 sometimes much dwarfed in stature, and have so weak a constitu- 

 tion that they are liable to premature death ; and we have seen 

 exactly parallel cases with the illegitimate seedlings of ^LijtTirinn 

 and Primula, Many hybrids are the most persistent and profuse 

 flowerers, as are some illegitimate plants. When a hybrid is 



crossed by either pure parent form, it is notoriously much more 

 fertile than when crossed inter se or by another hybrid; so when 

 an illegifcimate plant is fertilized by a legitimate plant, it is more 

 fertile than when fertilized inter se or by another illegitimate 

 plant. When two species are crossed and they produce numerous 



croisscs 



iween distinct species; and in regard to illegitimate unions I have given a 

 striking illustration in the ca-se oi Prim^ffa veris in a foot-note to my paper on 



Lifthrum, in Proc. Linn. Soc. vol. viii. (18t>4) p. 180 



