Races which Have Arisen Suddenly in Nature. 97 



those which serve to separate genera amongst the Cru- 

 ci ferae. 



The fruits of Capsclhi Heegeri are oval, and about 

 as thick as they are broad. The seeds are notorrhizous. 

 The valves lack the firm anatomical structure, character- 

 istic of the normal valve, but are soft and full of sap, 

 a condition which may be considered as due to arrested 

 development. On the weaker branches in the autumn, 

 deviations from this type occur which revert more or less 

 to that of C. Bursa; moreover the flowers and young- 

 fruits may develop into malformations, as the result of 

 the attacks of Cysfopus candidus, which closely resemble 

 those of C. Bursa pastoris. 



The seeds of isolated plants of C. Heegeri gave rise 

 solely to the parent type (382 examples) without rever- 

 sion to C. Bursa. 



There can therefore be scarcely any doubt that C. 

 Heegeri is a good elementary species which arose from 

 C. Bursa in 1897, or a few years previously, somewhere 

 near Landau. It is moreover a species which is dis- 

 tinguished from its nearest allies by characters of far 

 greater systematic importance than those which separate 

 many species of known origin. 



I myself found a S fella ria Holosfea a petal a not far 

 from Wageningen in Holland under similar circum- 

 stances (1889), and also in the same year the w^ell-known 

 Capsella Bursa Pastoris apetala^ near Horn in Lippe. 

 But I did not succeed in obtaining seed from either of 

 them. In 1888 I collected some seed of Lychnis vesper- 

 tina not far from Hilversum and obtained some per- 

 fectly glabrous plants by sowing it. The new variet\' 

 L. V. glabra proved fully constant as soon as I was able 



^ Sec Penzit,. Teratologic, T. p. 2C)y. 



