Seeds of Michigan Weeds Part 7

[Ill.u.s.tration: Fig. 88.]

=Hare's Ear.= _Conringia orientalis_ (L.) Dumort. Seeds brown, surface checked off into minute irregular pits or patches; broad oval, 2-2.5 mm.

long, in section nearly circular, except two opposite slight grooves near one side. Cotyledons inc.u.mbent. Introduced, not common.

[Ill.u.s.tration: Fig. 89.]

=Sand Rocket.= _Diplotaxis muralis_ (L.) DC. Flowers yellow, seeds reddish yellow or reddish brown, broad oval, somewhat flattened.

Mucilaginous when wet. Introduced from Europe. A vigorous weed.

[Ill.u.s.tration: Fig. 90.]

=Worm-seed or Treacle Mustard.= _Erysimum cheiranthoides_ L. Flowers yellow; seeds reddish yellow, smooth, dull, about 1.2 mm. long, ovoid or oval, more or less flattened, varying much in shape; some of them acute, rhombic or triangular, becoming mucilaginous when wet. Probably introduced from Europe. If not already in some portions of the state, we may at any time expect to find three other species of Erysimum. A vigorous and prominent weed.

[Ill.u.s.tration: Fig. 91.]

=Apetalous Pepper-Gra.s.s.= _Lepidium apetalum_ Willd. Petals usually wanting, sometimes 2 and minute; pods flat, nearly circular; seeds reddish yellow, flattened, ovate, 1.5-1.8 mm. long, or more exactly, nearly straight on one side and roundish on the other. Mucilaginous when wet. Cotyledons inc.u.mbent. When well developed in open places it becomes a tumble weed. Apparently naturalized from Europe.

[Ill.u.s.tration: Fig. 92.]

=Field Pepper-Gra.s.s or Cow Cress.= _Lepidium campestre_ (L.) R. Br.

Petals white; pods flat, nearly circular; seeds dull, dark brown, obovoid, with base acute, more or less flattened on three sides, 2-2.5 mm. long. Mucilaginous when wet. Cotyledons inc.u.mbent. Naturalized from Europe.

[Ill.u.s.tration: Fig. 93.]

=h.o.a.ry Cress.= _Lepidium Draba_ L. Seed reddish brown, surface slightly uneven, slightly flattened, oval to broad oval, 2-2.3 mm. long, usually with two slight vertical grooves on each side, inc.u.mbent. This may soon appear in Michigan.

[Ill.u.s.tration: Fig. 94.]

=Golden Pepper-gra.s.s.= _Lepidium sativum_ L. Seed reddish yellow to reddish brown, oval, slightly compressed, often nearly straight on one edge, usually showing two vertical grooves on each side, 2.5 mm. long, cotyledons inc.u.mbent. This is not a gra.s.s but a plant of the mustard family; it has escaped from cultivation.

[Ill.u.s.tration: Fig. 95.]

=Wild Pepper-Gra.s.s.= _Lepidium Virginic.u.m_ L. Petals white, pods flat, nearly circular; seeds granular, dull, reddish yellow, flat, ovoid with one edge straight, the other rounded, usually with a slight wing on the broad end and on the round edge. 1.5-1.8 mm. long. Mucilaginous when wet. Cotyledons acc.u.mbent.

When mature, large plants become tumble weeds. Apparently native to this country.

[Ill.u.s.tration: Fig. 96.]

=Ball Mustard.= _Neslia paniculata_ (L.) Desv. Small fruits, greenish to light yellowish-brown, globular, 2 mm. in diameter, covered with net-veined ridges; 1-2 seeded, cotyledons inc.u.mbent. Not yet known in Michigan but may arrive any time. Native of Europe.

[Ill.u.s.tration: Fig. 97.]

=Tall or Tumbling Mustard.= _Sisymbrium altissimum_ L. Flowers cream-color; pods long and narrow; seeds reddish yellow, oblong, about 1.5 mm. long, the apex winged. Mucilaginous when wet. Cotyledons inc.u.mbent. Introduced from Europe. One of the worst weeds in the northwest.

[Ill.u.s.tration: Fig. 98.]

=Hedge Mustard.= _Sisymbrium officinale_ (L.) Scop. Flowers yellow, seeds reddish brown or yellow, oblong, while lying on the flat side, circular in outline at the middle as viewed from the edge, straight on one side from the middle tapering to each end. 1-1.5 mm. long.

Mucilaginous when wet. Cotyledons inc.u.mbent. Introduced from Europe.

[Ill.u.s.tration: Fig. 99.]

=Penny Cress.= _Thlaspi arvense_ L. Flowers white; pods thin, double convex, nearly circular; seeds deep reddish brown, flat-oval or ovate, covered on each side by 12-14 curved ridges which originate and terminate at the narrow extremity. 1.5-2 mm. long. Cotyledons acc.u.mbent.

When eaten by cows the milk and meat has a disagreeable taste. A bad weed, especially in the north-west. Introduced from Europe.

ORPINE FAMILY. CRa.s.sULACEAE.

[Ill.u.s.tration: Fig. 100.]

=Mossy Stonecrop.= _Sedum acre_ L. Seed light, reddish-yellow, somewhat glossy, obovate to oblong, pointed at the base, slightly anatropous, compressed, 6-7 mm. long. This mossy little plant is persistent when once established in sandy soil. Introduced from Europe.

ROSE FAMILY. ROSACEAE.

[Ill.u.s.tration: Fig. 101.]

=Tall Hairy Agrimony.= _Agrimonia gryposepala_ Wahl. _Agrimonia hirsuta_ (Muhl.) Bicknell. Flowers yellow. Bur, consisting of calyx and two included fruits inside of which are two seeds; lower part of bur, top-shaped, rough, grooved, above which are numerous hooked p.r.i.c.kles in several rows, the whole 7-10 mm. long. Native of woods in this country; seeds mottled brown, flat on one side, 2.5 by 2.5 mm. not found mixed with gra.s.s seed. Several other species are nearly as troublesome as this one. Seldom found out of the woods.

[Ill.u.s.tration: Fig. 102.]

=Small-flowered Agrimony.= _Agrimonia parviflora_ Ait. Flowers yellow; fruit 5-6 mm. long and nearly as wide including the hooked bristles; bristles few, erect or spreading, scarcely any recurved; seeds light brown, broad oval, 2.7 by 2.5 mm. with a rounded point at the base more p.r.o.nounced than in the former species. Shady places.

[Ill.u.s.tration: Fig. 103.]

=Silvery Cinquefoil.= _Potentilla argentea_ L. Flowers yellow, achenes dull white to brown, unsymmetrically ovoid or short kidney-shaped, slightly flattened, 0.5-0.7 mm. long, smooth or marked by a few longitudinal curved ridges, some of them forked. Introduced into Michigan from Europe or possibly from the eastern states. Thrives in sandy land.

[Ill.u.s.tration: Fig. 104.]

=One kind of Cinquefoil or Five-finger.= _Potentilla Canadensis_ L.

Achene unsymmetrically ovoid, light straw-color to brown, ridges indistinct, short, wavy, branched and broken up, (these ridges are different from those of P. argentea or P. monspeliensis) 1 mm. long, the achene is less flattened and narrower in proportion. Native from Me. to Ga. Miss.

[Ill.u.s.tration: Fig. 105.]

=Rough Cinquefoil.= _Potentilla Monspeliensis_ L. Flowers yellow; achenes nearly white to light brown, unsymmetrically ovoid, or short kidney-shaped, slightly flattened, 1 mm. or less in length, clearly marked by a few longitudinal curved ridges, the longer ones forked.

Indigenous to Michigan, thriving on moist or wet land.

PULSE FAMILY. LEGUMINOSAE.

[Ill.u.s.tration: Fig. 106.]

=Ax Seed. Ax Wort.= _Coronilla scoparioides_ Koch. Seed reddish brown, oblong, slightly flattened and curved, 4-5 mm. long, 1.5 mm. wide, with a circular scar in a depression on the middle of one edge, and a slight ridge the entire length of both sides. Introduced from Europe, not yet a prominent weed in Michigan.

[Ill.u.s.tration: Fig. 107.]

=Bird's-foot Trefoil. Ground Honeysuckle. Bloom-fell.= _Lotus corniculatus_ L. Seed light brown occasionally mottled with black, s.h.i.+ning, spherical to ovoid, slightly compressed near one edge, 1-1.2 mm. in diameter, the compressed portion (raphe) extending half to three-fourths the length of the seed to the hilum or scar, above this the seed is narrower. Introduced from Europe. Seldom met with in this country.

[Ill.u.s.tration: Fig. 108.]