Volume JO Number 7 



The Plant World 



B ^aga3lne ot ©eneral JSotanis 

 JULY, 1907 



THE RELATION OF INJURY TO FASCIATION IN 

 THE EVENING PRIMROSES. 



By Alice Adelaide Knox. 



The fact that fasciation can be produced artificially bv 

 means of injury has been known for many years, and has become 

 especially familiar through Sachs' *experiments with Phaseolus 

 muItifio)-us and with Vicia faha. The method has been sunnnar- 

 ized by Goebel in his Organography, and both authors devote 

 some space to its discussion. The plants used are seedlings and 

 the injury is made at as early a stage as possible after germina- 

 tion. The mutilation consists in cutting or pinching off the 

 plumule so that the growth of the main axis is arrested. The 

 branches which develop thereafter in the axils of the cotyledons 

 are apt to be flattened, or banded. There may be one or more 

 of these secondary axes, and several of them may have the ab- 

 normal cross section. They do not keep their form permanently, 

 but revert to the normal as they grow. Their shape at first, 

 however, the irregular arrangement of the lea^'es, and the fork- 

 ing, or bifurcation of the axis, mark them as true fasciated 

 stems. Other species than Vicia and Phaseolus may be used, 

 and among the best of them are Agrostemna gitliago and Nas- 

 turtiums. 



The same phenomena may appear as the result of mutila- 

 tion at more advanced stages. Lamarlieref by cutting back 

 Barl-hausia faraxifolia succeeded in producing fasciated flower 

 heads, and Blaringham:}: ])roduccd fasciated panicles in Zea 



*Sachs, J. Gesammelte Abhandelunwn iiber Pflanzen-Phvsiologie 

 1:507. 1892. . t^ > 



fLarmarliere, G. de, Sur la production experimentale des tiges et 

 d'infloiescences fasciees. Comptes Rendus. Paris, 128:1601, 1899. 



^Blaringham, L. Anomalies hereditaires provoquees par des trauma- 

 tismes. Comptes Rendus, Paris, 190:378. 1905. 



