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PREFACE 
The present volume of Aster Studies discusses the specific 
limits, life-history and variability of Asters, and also begins the 
systematic treatment of Aster species ; in fulfilment of investiga- 
tions which commenced in 1886. The descriptions comprise the 
Biotian section of the genus, a section confined to North America, 
and including 84 species (58 of which are here first published or 
characterized) * and 10 subspecies ; each of which is illustrated by 
one or more figures ; in all 108 figures, 13 of which are heliotype 
plates, the others being cuts in zinc. About 250 subordinate 
forms are also briefly characterized. 
In a former volume, the History of Pre-Clusian Botany in its 
relation to Aster, t I have traced the progress of the monotype 
conception of Aster from the Greeks onward through the year 
1600. Distinct establishment of Aster as a polytype genus came 
with Clusius, beginning with 1576 and culminating in 1601. 
Rapid increase followed in the number of new species attributed 
to Aster, species which have since been assigned to Conyza, Inula, 
Pulicaria, etc. The next two centuries may be termed the Clusian 
and the Linnaean periods of Aster history ; the former including, 
and the latter excluding, numerous yellow-rayed relatives. To 
dwell upon these periods is not at present pertinent, for the details 
of Aster history, as previously remarked, are better presented, 
after Clusius, group by group and species by species. The his- 
torical matter in the present volume consists instead, Ist, of a sketch 
of Aster as a genus with its segregations and recombinations since 
1600 (pp. 51-58) ; 2d, a detailed historical review of the Biotian 
group to date, with notice of authors, early collectors, etc. (pp. 
59-80) ; and 3d, separate historical sketches of such species as 
have already a history (p. 107, etc.). 
* Of the species here first characterized, two, A. ambiguus and A. subcymosus, 
nt names given to herbarium material by Bernhardi ; one, 4. viridis, is simi- 
larly credited to Nees; another, Æ. sudinteger, similarly to Mr. E. P. Bicknell ; five 
were formerly described by me as the varieties 4. divaricatus persaliens, A. curvescens 
: eer Wes Ww edad visis eG macrophy lus excelsiorand A. macrophyllus 
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