264 Retrograde Varieties 



the mixed characters. Both parents bear large 

 capsules with an abundance of seed, but in the 

 hybrids the capsules remain narrow and weak, 

 ripening not more than one-tenth the usual 

 quantity of seed. Both parents are easily 

 cultivated in annual generations and the same 

 holds good for the hybrid. But whereas the 

 hybrid of muricata and biennis is a stout plant, 

 this type is weak with badly developed foliage, 

 and very long strict spikes. Perhaps it was 

 not able to withstand the bad weather of the 

 last few years. 



A goodly number of constant hybrids are de- 

 scribed in literature, or cultivated in fields and 

 gardens. In such cases the essential question 

 is not whether they are now constant, but 

 whether they have been so from the beginning, 

 or whether they prove to be constant whenever 

 the original cross is repeated. For constant 

 hybrids may also be the issue of incipient split- 

 tings, as we shall soon see. 



Among other examples we may begin with 

 the hybrid alfalfa or hybrid lucerne {Medicago 

 media). It often originates spontaneously be- 

 tween the common purple lucerne or alfalfa 

 and its wild ally with yellow flowers and pro- 

 cumbent stems, the Medicago falcata. This 

 hybrid is cultivated in some parts of Grermany 

 on a large scale, as it is more productive than 



