straight
or curved, apex truncate, base abruptly tapering, cylindrical, the sides
bearing 10 narrow, vertical ridges. Introduced from Europe. In Eastern
New York and Western Massachusetts meadows abound in large areas of this
vile weed, 1.8-2.2 mm. long.

[Illustration: Fig. 201.]

=Mouse-Ear Hawkweed.= _Hieracium Pilosella_ L. Flowers yellow; achenes
jet black, oblong, straight or curved, apex truncate, base abruptly
pointed, cylindrical or narrowly oval, the sides bearing 10 narrow
vertical ridges. Introduced from Europe. The achenes very closely
resemble those of the orange hawkweed. It doesn't matter much, for the
habits are the same, and one is about as noxious as the other.
Introduced from Europe.

[Illustration: Fig. 202.]

=Elecampane.= _Inula Helenium_ L. Flowers yellow; achenes light brown,
straight or curved, linear, flattened, 4-5 mm. long, 4 sided with 5-8
obscure vertical ridges on each side, apex concave, the margin bearing a
circle of short stiff bristles, the remains of longer ones. Introduced
from Europe. Not common.

[Illustration: Fig. 203.]

=Marsh Elder.= _Iva xanthiifolia_ (Fresen.) Nutt. Achenes various shades
of brown to black, flattened or rhombic in section, obovoid, 1.5-2 mm.
long, longitudinally, striate with fine lines. Native to the upper
peninsula of Michigan where it most likely was at one time introduced
from the west. It has not been found in the lower peninsula, probably
because it had no means of coming across Lake Michigan.

[Illustration: Fig. 204.]

=Wild Lettuce.= _Lactuca Canadensis_ L. Flowers yellow; achenes black or
nearly so, flattened, oval, bearing 3 ribs, the lateral ones sometimes
double, the middle one slender, surface abounding in minute transverse
ridges as seen under a lens, the remains of a beak sometimes remaining.
Native of this country. Other species of Lettuce are more or less
troublesome.

[Illustration: Fig. 205.]

=Prickly Lettuce.= _Lactuca virosa_ L. For many years erroneously called
_Lactuca scariola_. Flowers yellow; achenes dull, dark brown, mottled
with black, flattened, bearing 5-7 rough, vertical ridges, interspersed
by as many smaller ones; oblong, obovate, widest toward the tapering
apex. 3-3.5 mm. long. Some of the leaves turn one edge up and the other
down. Introduced from Europe and has proved itself a remarkable
traveller.

[Illustration: Fig. 206.]

=Fall Dandelion.= _Leontodon autumnalis_ L. Flowers yellow; achenes
light bro