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1919] Long,— Eragrostis peregrina 135 
exist — either single or opposite branches at the base of the panicle. 
Professor Wiegand notes that “The branches of the panicle...are 
sometimes solitary in smaller forms of E. pilosa (including E. Purshii).” 
These forms are probably E. Purshii, not true E. pilosa. But it will 
be agreed, doubtless, that the value of a character so palpably de- 
pendent upon normal growth need not be discounted by casual small 
forms. 
The absence of the hairs in the axils of the panicle-branches appears 
to be perfectly constant in E. peregrina and therefore diagnostic 
for the species. Hackel notes that they are, however, sometimes 
absent in E. pilosa; the same is to be said of E. Purshii: hence this 
character must be valued accordingly. 
Hackel’s statement that in ŒE. peregrina “the branches of the 
panicle are spikelet-bearing to the base so that the panicle appears 
much denser” while in E. pilosa they are “branched from the one- 
third or one-half point upward and loosely provided with spikelets "' 
describes the condition in these two species perhaps sufficiently 
accurately, but Professor Wiegand’s phrasing, in the case of E. pere- 
grina, “spikelet-bearing to near the base," is certainly preferable. 
Professor Wiegand's comment,...* E. pilosa (including E. Purshii) 
...in smaller plants of the latter species the spikelets extend far 
toward the base of the branches," was apparently induced by his 
comparison with plants of true E. Purshii. This last species rather 
characteristically has spikelets arising from quite near the bases of the 
branches. This character technically distinguishes E. peregrina from 
E. pilosa but not from E. Purshii. Another point: E. Purshii as well 
as E. pilosa having open, sparse panicles, obviously the denseness of 
the panicle in E. peregrina is not alone due to the panicle-branches 
being spikelet-bearing to the bases, as Hackel seems to infer. The 
point to be noted is that the panicle of E. peregrina bears up to five 
or more times as many spikelets as either of its allies. When A 
numerical character becomes as tangible as in this case, it assumes 
as much importance, it is believed, as is commonly accredited the 
number of florets in a spikelet in this genus. 
_ The spikelets show characters of more or less differentiating value. 
The shape appears to be rather distinctive. In E. peregrina it is 
characteristically ovate or ovate-oblong; in E. Purshii, ovate-lanceo- 
late; in E. pilosa, tending to be linear. In the width of spikelet Æ. 
peregrina is practically indistinguishable from E. Purshii but rather 
