82 Rhodora [May 
variety. It was found impracticable to indicate the length of the 
body of the glume or lemma because of the gradual transition into 
the awn. In the text all measurements in length of these two organs 
include the awn. A much better and more definite indication of the 
size of the floret is found in the palet, the apex of which is easily recog- 
nizable. The degree of pubescence of both the florets and the foliage 
varies widely in nearly every species, yet in some cases it seems to 
indicate a more or less definite varietal or even specific difference. 
The breadth, induration and form of the glumes have long been used in 
distinguishing the species, and in our study also prove of great value. 
There is, however, much variation of these organs in E. virginicus and 
E. robustus. 
Much of the previous difficulty in Elymus was due to the failure 
to recognize the species here described as new. This has for years 
formed a large portion of the material passing as E. canadensis. 
Further confusion has arisen through the failure to differentiate 
between E. canadensis and E. robustus along what now seem to be the 
proper specific lines. The present paper deals only with E. virginicus, 
E. canadensis and their immediate allies. These form a rather natural 
group, from which E. arenarius, E. glaucus, and other species may be 
excluded. 
SYNOPSIS AND KEY TO THE SPECIES TREATED. 
a. Awnsstraight (when mature and dry): palet 5.2-8 (rarely 8.5- 
9.2 in E. virginicus) mm. long b. 
b. Glumes broad (0.9-2 mm. wide), strongly indurated and 
more or less curved at the base c. 
c. Glumes 1-2.7 em. long: lemmas 1-3 em. long d. 
d. Glumes and lemmas more or less awned e. 
e. Lemmas and glumes glabrous or merely scabrous on 
the margins f 
f. Leaves flat: spikes usually included at the base. . E. virginicus. 
J. Leaves involute when dry, narrower: spikes 
mostly exserted: plant lower....2. virgin., var. halophilus. 
e. Lemmas and glumes villous-hirsute. . E. virgin., var. hirsutiglumis. 
d. Glumes and lemmas awnless or nearly so 
E. virgin., var. submuticus. 
c. Glumes 2.7—4 em. long: lemmas (2.8—) 3.5-4.5 em. long: 
spikes exserted g. 
g. Glumes and lemmas villous-hirsute................ E. australis. 
g. Glumes and lemmas strigose-scabrous or glabrous. 
E. aust., var. glabriflorus. 
b. Glumes narrow, often setiform (0.4-0.8 mm. wide), indu- 
rated and terete below, essentially straight A. 
h. Palet 7.5-8 mm. long: rachis-joints 3-4.5 (rarely 5-8) 
mm. long: spikelets 2—4-flowered: leaves and sheaths 
OS PR N E E rr re E. riparius. 
