YALUE OF CHARACTERS. 359 
possibly act some part in influencing the dissemination of the 
pollen, although nothing in that respect has as yet been ascer- 
tained. These appendages are uniform throughout the order, ex- 
cept as to length or breadth, and except as to two subtribes whieh 
they assist in characterizing. [In the subtribe Piqueriee of Eupa- 
toriacez they are deficient, the anthers being truncate on the top ; 
and in the subtribe Ambrosice of Helianthoidee they taper into 
an incurved point. In one or perhaps a very few species of 
Helianthoidex, they are reduced to a small point or possibly 
deficient. 
At the base of the anthers the appendages usually called tails 
are much more systematically valuable, as affording by their pre- 
sence or absence almost absolute tests of several of the largest 
tribes. The difficulty is, in a few cases, to decide whether the 
anthers are or are not to be properly designated as tailed; and 
allowance must be made for a few, although rare, real exceptions. 
First, as to determining what is a tail to an anther, the accom- 
panying figures (Plate 1X.) will readily explain the principal differ- 
ences. In figs. 1 and 2 the anthers are truncate at the base; in 
fig. 3 produced into obtuse auricles; in fig. 4 sagittate with the 
auricles of adjoining anthers connate to the point, in fig. 5 sagit- 
tate with the auricles free; and in all these they are inappendi- 
culate or tailless, although the auricles in figs. 4 and 5 may be 
very acute, for the points are not produced beyond the pollen- 
bearing cells; in figs. 6 and 7 these auricles, united in fig. 6, 
distinct in fig. 7, are very shortly produced into what may be 
termed rudimentary tails, and occasion one of the great diffi- 
culties, as different botanists have described them as tailed or 
tailless ; in figs. 8 and 9 the tails are decidedly setiform, those of 
adjoining anthers united so as to show five setze to the pentamer- 
ous andreecium in fig. 8; setiform but distinct in fig. 9, showing 
ten sete either approximate in pairs or equidistant as represented 
in the plate, or lying close to the filament; the tails are ciliate 
at the end or ciliately fringed in figs. 9 and 10, dilated and 
fringed in fig. 11. But the observation of some of these differences 
requires eonsiderable care and some experience. If not well 
soaked out, the acute auricles of figs. 4 and 5 may be mistaken 
for the really pointed ones of figs. 6 and 7 ; and the tails of fig. 7, 
and even of fig. 9, sometimes lie so close to the filament, that 
when very fine they are frequently overlooked. To show the 
degree of constancy of these various forms we may take the thir- 
