Systematic Atavism 635 



some years it is seen to return to atavistic con- 

 ditions in some rare individuals. More than 

 once I have observed such cases myself, and 

 found that the variation is only a partial one, 

 producing one or rarely two umbels on the same 

 plant, and liable to fail of repetition when the 

 varying specimens are transplanted into the 

 garden for further observation. But the fact 

 remains that scapes occur. The scapes them- 

 selves are of varying length, often very short, 

 and seldom long, and their umbels display the 

 involucre of bracts in a manner quite analogous 

 to that of the Primula officinalis and P. elatior. 

 To my mind this curious anomaly strongly sup- 

 ports the view of the latent condition of the 

 scape in the acaulescent species, and that such a 

 dormant character must be due to a descent 

 from ancestors with active scapes, seems to be in 

 no need of further reiteration. Eetuming to 

 activity the scapes at once show a full develop- 

 ment, in no way inferior to that of the allied 

 forms, and only unstable in respect to their 

 length. 



A second example is afforded by the bracts 

 of the crucifers. This group is easily distin- 

 guished by its cruciform petals and the group- 

 ing of the flowers into long racemes. In other 

 families each flower of such an inflorescence 

 would be subtended by a bract, according to the 



