148 AMERICAN MIDLAND NATURALIST 
This elegant species is not unusual in yards or in moderately 
damp, rich prairie soil, and was collected by the writer on August 
27, 1911, at Leeds, Benson County. 
Aster durus sp. nov. 
Caulis de rhizomate longo, gracili, horizontali oriens, erectus, 
gracilis, purpurascens, subsimplex, vel ramis erectis vel adscen- 
dentibus, in plantis redundantibus, permaturis interdum late 
divaricatis vestitus, lineis pubescentiae longitudinalibus de folliis 
decurrentibus, praeterea glaber, 3-5 dm. altus. Folia anguste 
usque lineari-lanceolata, 5-10 cm. longa, 5—10 mm. lata, ambobus 
extremitatibus angustata, sessilia, minutatim serrulata vel integra, 
marginibus ciliatis, praeterea glabra. Inflorescentia paniculata, 
contracta. Involucrum 6-8 mm. altum, 8-r1o mm. latum, bracteis 
eius in 4 series dispositis, lanceolatis, acutis, cilio- et scarioso- 
marginatis, praeterea viridibus. Flores radiati 25-35, 5-8 mm. 
longi, pallide violaceo-purpurei vel albi. Pappus sordide albidus. 
Stem from a very long, slender, horizontal rootstock, erect, 
slender, purplish, subsimple or with erect or ascending, in large, 
old plants sometimes widely divaricate branches, with longitudinal 
lines of pubescence decurrent from the leaves, else glabrous, 3-5 
dm. high. Leaves narrowly to linear-lanceolate, 5-10 cm. long, 
5-10 mm .wide, narrowed to both ends, sessile, minutely serrulate 
or entire, with ciliate margins, else glabrous. Inflorescence pani- 
culate, contracted. Involucre 6-8 mm. high, 8-10 mm. broad, 
its bracts in 4 rows, lanceolate, acute, ciliate and scarious-margined, 
else green. Rays 25-35, 5-8 mm. long, pale violet-purple to white. 
Pappus grayish white. 
Species easily confounded with this are A. Jautus Wunell, 
which is best recognized by its widely spreading inflorescence; 
A. salicifolius Yam., which has thickish, broader leaves and the 
disk of the head 1 cm. high and 1 cm. broad, and white pappus; 
A. longtfolius Lam., which has the bracts of the involucre glabrous, 
subequal, only the outermost sometimes shorter, and pale pappus; 
and A. laetevirens Greene, which has rather few heads, broader 
leaves, involucral bracts with white mid-rib, and outer bracts 
broader than the inner. 
This species has a predilection for the margins of sloughs. 
The type specimen was collected by the writer on September 6, 
1910, in high grass around a slough, not far from Leeds, Benson 
