g. 152.]

=Red Root. Wheat Thief. Corn Gromwell.= _Lithospermum arvense_ L.
Flowers white; ovary 4-divided separating into four hard, conical-ovoid
achenes, each dull gray, erect, wrinkled, 2.5-3 mm. long, convex on the
back, keeled on the inner side, base obliquely truncate, containing two
minute white tubercles. A prominent weed of high rank in fields of
winter wheat.

VERVAIN FAMILY. VERBENACEAE.

[Illustration: Fig. 153.]

=Blue Vervain.= _Verbena hastata_ L. Achenes crowded, four together
until mature, dull, reddish brown, flattened, oblong, 1.7-2 mm. long,
bordered by a narrow margin, the outer face convex, bearing 3-5 small
vertical ridges branching and uniting at the apex, forming a distinct
network, the inner face sloping to the margin from a central vertical
ridge; a light colored scar is seen on one side of the base. Native to
this country. Not important.

[Illustration: Fig. 154.]

=Nettle-leaved Vervain.= _Verbena urticifolia_ L. Achenes 1.6-1.8 mm.
long, very closely resembling the last above mentioned. The achenes of
this one are a trifle shorter and broader, more nearly oval than oblong.
Native to this country. Not common in fields.

MINT FAMILY. LABIATAE.

[Illustration: Fig. 155.]

=Dead Nettle.= _Lamium amplexicaule_ L. Achenes light brown,
conspicuously marked by white spots some of which coalesce making the
surface striped crosswise, obovate-oblong, pointed at the smaller end,
1.5-2 mm. long, the outer surface rounded, the inner face angled, the
concave surfaces sloping to the edges from a central vertical ridge.
Introduced from Europe. Thrives in cool weather.

[Illustration: Fig. 156.]

=Motherwort.= _Leonurus Cardiaca_ L. Achenes light brown,
obovoid-oblong, rounded on one side flat on the other two sides, the
truncate apex hairy, 2-2.4 mm. long. Introduced from Europe. Waste
places.

[Illustration: Fig. 157.]

=White Hoarhound.= _Marubium vulgare_ L. Achenes dull, varying from
light to dark brown, sometimes finely roughened by numerous minute
tubercles, slightly flattened, oval or obovoid, about 2 mm. long, outer
surface convex, inner face angled sloping to the edges from a central
vertical ridge, edges of achenes often slightly margined, surface
lightly grooved. Introduced from Europe. A weed in northern Michigan
where snow protects it in winter.

[Illustration: Fig. 158.]

=Catnip. Catmint.= _Nepeta Cataria_ L. Achenes dull, light reddish brown
to nearly black, with t