ar faces, extending along the upper half. Achene, 3-4 mm. long,
having twelve longitudinal ridges, 1.2 mm. wide. Introduced from Europe.
Troublesome on thin lawns.

[Illustration: Fig. 213.]

=Salsify. Oyster-Plant.= _Tragopogon porrifolius_ L. Flowers purple;
achenes dull light brown, nearly cylindrical; apex tapering, mostly
terminating in a slender beak which is often longer than the body of the
achene. Achene straight or curved, 10-ribbed, 12-18 mm. long, outermost
coarsely roughened by upwardly directed, whitish, scale-like
projections. Native of Europe.

=Meadow Salsify. Yellow Goat's Beard.= _Tragopogon pratensis_ L. Flowers
yellow; achenes dull, light brown, nearly cylindrical, apex tapering,
mostly terminating in a slender beak. Achene straight or curved,
10-ribbed, 12-15 mm. long, the inner ones of the head smooth, the
outer-most coarsely roughened by upwardly directed, whitish, scale-like
projections. Introduced from Europe.

[Illustration: Fig. 214.]

=American Cocklebur.= _Xanthium Canadensis_ Mill. Achenes or burs
reddish brown, oblong, circular in section, two-beaked, about 20 mm.
long, covered with stout hooked prickles. Each bur encloses two seeds.
Native of this country.

[Illustration: Fig. 215.]

=Spiny Clotbur.= _Xanthium spinosum_ L. Bur oblong, light brown, very
slightly flattened, 10-13 mm. long, the beaks weak and small, small
hooked prickles 3-4 mm. long, each bur contains two seeds. Introduced
from Europe.

=Broad Cocklebur.= _Xanthium strumarium_ L. Bur dark brown, oval,
circular in sections 12-22 mm. long, beaks stout, nearly straight,
spines about 5 mm. long, surface of burs and base of spines clothed with
minute hooked prickles. Naturalized from Europe.

INDEX.

Page

Abutilon, 145

Acalypha, 143

AC-CUM'BENT, leaning or lying upon, applied to cotyledons when
the caulicle (radicle) is folded against their contiguous edges,
shown as [Symbol: 0== rotated 90 deg. clockwise].

A-CHENE', achenium, a small, dry, one-seeded, indehiscent fruit,
likely to be mistaken for a seed.

Achillea, 160

Acnida, 126

A-CU'MIN-ATE, ending in a prolonged tapering point.

Agrimonia, 138

Agrimony, tall hairy, 138

Agrostemma, 128

Agropyron, 110

Aizoaceae, 128

Alfalfa, 140

Allium, 119

Alfilaria, 142

Alsike clover, 141

Alsine, 131

Alyssum, 1