Explanation of the plate 



(Tavle Ij. 



Fig. 1 . Old corymb of H. excellens. 



— 2. Young corymb of the same. 



— 3. Scape with terminal head of //. pilosella. 



— 4. Corymb of H. aurantiacum. 



— 5. Corymb of //. excellens x aurantiacum, cf. 



— 6. H. excellens X pilosella. Ç. 



— 7. H. pilosella x aurantiacum. 



— 8. Female head of a form of H. pilosella. 



All the main figures are natural size; the detail-figures which give 

 the form of the outer flowers of each plant are magnified twice. 



