THE GENUS ASTER. 



7 



change to almost any of the large genera of flowering plants, 

 but they are of importance from a practical point of view when 

 we consider the capabilities of any given group for improvement 

 under cultivation. Moreover, the existence of such intermediate 

 forms renders possible the application- of that most valuable of 

 all horticultural aids — hybridisation. Although its use is by no 

 means confined to the large genera, it is in these rather than in 

 the small genera that the process has been most uniformly suc- 

 cessful. Nature herself has taken this matter in hand in the 



Fig. 1. — Aster alpinus. (From the Dictionary of Gardening.) 



genus Aster, and given us hybrids which, however perplexing 

 they may be to the systematise, are full of promise to the experi- 

 mental physiologist and horticulturist. 



The first American subgenus, Amellastrum, contains a 

 single species, A. alpinus (fig. 1), which, like many other plants 

 of high altitudes and latitudes, is found also in the colder regions 

 of other continents. The second subgenus, Megalastrum, has 

 two large-flowered species, both belonging to the hills of our 

 South-west. The long rays would make these species of interest 

 in an experimental garden were it not for the peculiar conditions 

 — namely, those of a dryish country — under which they occur. 



