230 



A NEW BRITISH SPECIES OF SENECIO 



Fig. 2. Senecio camhrensis Rosser. (a) Capitulum at time when ray florets are fully expanded (x 5); (b) a 

 single involucral bract (x 10); (c) ray floret (x 10); (d) cypsela (x 20); and (e) the surface of the c>psela 



( X 160). 



First Record 



Near Cefn-y-bedd, 15-8-1948, H. E. Green in Herb. MANCH. 



Reference has already been made to the experimental evidence provided by 

 Professor Harland and Miss Jackson, whose synthesis of S. camhrensis has shown that it 

 is an allopolyploid which appears to have originated at Ffrith very recently by hybridi- 

 sation between S. squalidus and S. vulgaris, followed by doubling of the chromosomes. 

 Both the naturally-occurring and synthetic plants were exhibited at the Exhibition Meeting 

 of the Botanical Society in November, 1954, already reported (Lousley, 1955). 



The present population at the type locality includes some plants of S. vulgaris (non- 

 radiate) and though the hybrid S. X baxteri Druce could not be found in the vicinity 

 S. squalidus was collected a few miles away. The wild plant shows little variation; plants 

 grown in the greenhouse from seed collected at Ffrith differ from those in the wild 



