84 SYSTEMATIC DESCRIPTION OF ASTERS 
ancestry by continued development, while remaining in similar 
environment, of a body of characteristics which show a consider- 
able difference from their nearest allies. A distinct group which 
continues its kind; either observed not to revert quickly to a 
diverse parent form, or sustaining such a comparison with other 
better known species as to make non-reversion probable. 
Subspecies. More easily or frequently passing back into its 
parent form than does the species. 
Variety. Not used; better referred to horticultural use. 
Form. Indefinite group-term not predicating rank ; and thus 
applicable to species, subspecies or subordinate form. 
State. Useful occasionally when speaking of less separable 
groups which seem so plastic as to be of doubtful permanence, 
their characters seeming assignable to the immediate environment. 
Can be used of a slight variation without implying that it is not 
to be classed under the typical form. 
Condition. Useful occasionally in speaking of a temporary 
stage of growth or activity during part of an individual life-his- 
tory as ‘‘a prostrated or an impoverished or a floriferous condition 
of an axilliferous state of Aster divaricatus.” 
LIMITATION OF OTHER TERMS 
Pedicels, the ultimate branchlets, each supporting a single head 
of flowers. 
Bractlets, leaves on pedicels, whether minute or not. 
Bracteals, any leaves closely investing or subtending the in- 
florescence or a part of it, whether they are homologous with 
bractlets, rameals or axiles. 
Bracts, the involucral bracts or scales. 
Tips, the dark portion of the bracts just within the apex, 
usually thickened with green cellular tissue. 
Apices, the apices of the bracts. Chanfer or bevel-tip bracts, 
those with apex cut off at the sides, 7. e., terminated by a broad 
low triangle. 
Bases, the bases of the leaves. 
Wings, the wing-like dilation of certain petioles. 
Primordials, early-developed and soon-perishing little leaves on 
radical shoots, preceding the genuine radicals and usually succeed- 
ing a few transient phyllodes. 
