380 The Botanical Gazette. [October, _ 
In the preparation of this paper, two types of achenial — 
hairs have been observed: 1. a simple, pointed hair having, — 
apparently, no median line or division wall; 2. a compound — 
or double hair, branching so as to form a double-pointed 
apex. The former will be designated as ‘‘simple” and the — 
latter, with all modifications, will be included under ‘‘duplex 
. > ' 
hairs,” a term used by Macloskie. : 
Of the entire list studied, the only simple hairs found were 
in Rudbeckia and Centaurea. 7 
Those found to bear duplex hairs are Eupatorium, Aster, 
Coreopsis, Dysodia, Bigelovia, Bidens, Kuhnia, and Liatris 
As may be seen, this division does not follow closely the 
established lines of group division. Aside from the digres- 
sion already noted by Macloskie in the group Cynaroidea 4q 
may be mentioned the fact that Centaurea, of this same — 
group, has long simple hairs. This puts into one group the 
three possible divisions which may be made with reference to — 
achenial hairs. In the Helianthoidee also several genera, a — 
Helianthus, Coreopsis, and Bidens, present distinct duplex : 
hairs; on Lepachys they are of the simple kind and on sa 4 
thium and Silphium no hairs are found. Among the abe q 
oidee, the genera Aster and Bigelovia have conspicuous 4 
plex hairs while on others, as Grindelia and Erigerom, 1 - 
hairs are found. : q 
In other groups similar differences occur which sare : 
to preclude the possibility, or at least the advisa mir 4 
accepting these as tribal characters. Within the or taal ut 
ever, the character seems to be more constant an he q 
perhaps, be made of value in the determination of specie vey 
In Eupatorium villosum Swartz the hairs a or tole | 
short and have lateral canals which appear also to erg wks 
low the division wall in those duplex hairs in whic Il in some 
is visible. Whether the non-appearance of this pe se hait 
duplex hairs was due to the accidental placing a strucy 
upon the slide or to the fact that this is an incon 4 
tural character, the writer was unable to peerre first 
In Liatris gracilis Pursh a number of rag: An revealed, 
examined appeared simple, but closer invest ee 
in nearly every case, a rudimentary §f In these hairs cross 
lishing the duplex character of the hatr. n application 
te 
canals were plainly noticeable, especially after the i 
of glycerine. : 
