220 DESCRIPTION OF ASTER; DIVARICATI 
rank in Aster, if it stood alone; but it is here reinforced, 2d, by 
the failure to observe other similar specimens, though searched for 
in the original locality, 1899 to 1905; and 3d, by the nature. 
of the building-operations by its side, leading to the conclusion 
that it was a stimulated form, altered by a sudden loosening of its 
soil and by rich accession of material ; the spot being abandoned 
by builders, luxuriant growth set in. 
The tendency to verticillate development seems a freak ; no 
fungus or insect-swellings appear associated ; and the possible ex- 
Verticil form 
of r laytoni 
Fic. 41. 
E 
planation of suppression of upper internodes because of a sup- 
posed drought seems unsatisfactory, because, 1st, other neighbor- 
ing plants of A. divaricatus were not so affected, and 2d, because 
e presence of at least 3 successive verticils would on that hypo- 
thesis call for the improbable alternation of as many periods of 
drought and moisture. 
l The smoothness of the leaves points to A. divaricatus, but 
their shape and the form of the inflorescence-clusters indicate a 
nearer affinity to A. Claytoni. 
