CRUCIFER^ 13 



of its introduction and is the means of its distribution 

 and its permanence in this country. 



Alyssum maritimum, Lam. Native in the Mediter- 

 ranean region and in the Canary Islands. Being a 

 favourite garden plant in Britain and remarkably hardy, 

 the plant is frequently found in a semi-wild state near 

 gardens, and has even become naturalised in a few spots. 



Arabis albida, Stev. Indigenous in the rocky hills of 

 South-East Europe and Western Asia. It is a favourite 

 cottage garden plant, and is not infrequently recorded 

 as an escape and even occasionally as naturalised on old 

 walls. 



Arabis alpiua, L. A native of the Alps of Europe and 

 of the extreme North. It has been recorded in one or 

 two places in England as an escape from gardens. 



Arabis arenosa, Scop. The native range of this 

 species extends from Belgium and Southern Sweden 

 to Central Europe. It would not therefore be sur- 

 prising to hear of its discovery in stony places in 

 Southern England. It has, however, so far only been 

 recorded in connection Math weeds introduced with 

 foreign grain. 



Arabis Turrita, L. Native of stony woods and rocky 

 slopes in the greater part of Europe, Northern Africa, 

 and Western Asia, but not reaching Holland or 

 Northern France. It has long been known in Eng- 

 land as a denizen on old walls, and as the first records 

 were from the neighbourhood of Botanic Gardens it is 

 quite possible that it originally spread from them. 



