Macbride and Payson — Erigeron, Series Multifidi 73 
and ray flowers. In the present paper these characters have been 
considered as showing varietal differences only. 
Theoretically every species might have four different varieties, 
two of which would be pubescent and two glabrous and of the two 
glabrous ones, one would be radiate and one discoid. Similarly 
there would be a radiate and a discoid variety of the pubescent 
pair. Asa matter of fact all four combinations have been found in 
E. compositus and E. trifidus. In E. pinnatisectus, however, the 
pubescent character seems to be entirely lacking and so we find 
only two varieties — the radiate and the discoid. 
Practically all individuals of FE. compositus and E. iritidus develop 
cilia on the petioles and leaf margins and when a plant is spoken of 
as ‘‘ glabrous ”’ it is only the surface of the leaf-blades proper that 
are considered. Pubescent and glabrous forms merge but little 
and there is, in general, but little difficulty in separating them. 
Similarly, radiate and discoid varieties are easily separable, 
although forms appear that are intermediate. We have treated all 
forms as discoid in which the rays are not conspicuous. Specimens 
cited are in the Gray Herbarium unless followed by the abbrevia- 
tion ‘“ R. Mt. Herb.”’ indicating that they are in the Rocky Moun- 
tain Herbarium. 
The only group-name which we know for this aggregation of 
species and varieties is the Multifidi of Rydberg, Fl. Colo. 359 
(1906). Unfortunately the author has failed to indicate the status 
of this group in classification but from the fact that the name is 
given in the plural form and appears to be just above the rank of 
species it may well be considered as designating a series which may 
be defined as follows: 
ERIGERON, series Muutirip1 Rydberg, Fl. Colo. 360 (1906). 
Perennial, cespitose, arctic and alpine herbs; leaves clustered on 
the very short t stems; deeply ternately or pin nnately dissected ; 
petioles and leaf-margins generally ciliate (except in E. pinnati- 
sectus); heads usually numerous, apd on scapose peduncles, 
radiate or discoid: achenes pubesce 
