CRUCIFER^ 29- 



Sisymbrium Irio, L. The range of the species is from 

 Europe to India, but nowhere within this area are its 

 habitats given as obviously natural ones. Its abundance 

 in Afghanistan and parts of Northern India suggests that 

 this region may be its home. In Europe it is a weed 

 of cultivation, of waste places, and of roadsides. It 

 was abundant about London in the seventeenth century^ 

 and its appearance in the streets after the Great Fire 

 led to its name of London Rocket. It did not appear 

 for the first time after the fire, as some have sup- 

 posed, for both Merrett and Ray expressly state that 

 it was common in the suburbs of London during 

 the years preceding 1667. That it was then a recent 

 introduction is, however, suggested by the fact that 

 Parkinson, writing in 1640, did not know it as an 

 English plant. 



Sisymbrium junceum, Bieb. A native of Eastern 

 Europe and Western Asia which has once been recorded 

 from Yorkshire as a waste ground alien. 



Sisymbrium Loeselii, L. A native of Central Asia 

 which has been noticed on waste ground in England 

 on many occasions in recent years. 



Sisymbrium pannonicum, Jacq. One of those way-^ 

 side and waste ground weeds the native limits of which 

 it is most difficult to determine. It is undoubtedly 

 native in Eastern Europe and Central Asia, being very- 

 common, for instance, in the deserts about the Caspian 

 Sea. In England its status is also undoubted, for it 

 only occurs sporadically and temporarily as a waste 

 ground introduction. 



