[Ill.u.s.tration: Fig. 49.]

=Oak-leaved Goosefoot.= _Chenopodium glauc.u.m_ L. Concerning the different stages of cleaning note remarks above under C. alb.u.m.

Seeds brown to black, more or less slightly granular, shining, flattened on two sides, circular edge bluntly rounded, with a single notch from which on one side extends a slight depression toward the center of the face, .5-.8 mm. in diameter. Introduced from Europe. Occasional on moist soil.

[Ill.u.s.tration: Fig. 50.]

=Maple-leaved Goosefoot.= _Chenopodium hybridum_ L. Concerning the different stages of cleaning, note remarks above under C. alb.u.m.

Seeds black, shining, greenish gray if not fully cleaned, nearly circular, lens-shaped, equally convex, 1.2-1.8 mm. in diameter, with a notch on the edge, from which on one side a groove leads to near the center of the face, surface finely uneven, often with a faintly evident radiating striation. Native of this country. Of little importance.

[Ill.u.s.tration: Fig. 51.]

=Many-seeded Goosefoot.= _Chenopodium polyspermum_ L. Concerning different stages of cleaning, note remarks above under C. alb.u.m.

Seeds finely glandular, shining, jet-black, greenish gray, when not fully cleaned, nearly circular or broadly kidney-shaped, sides equally convex, .6-1.1 mm. in diameter, with a notch on the edge from which on one side, a groove leads to near the center of the face. Introduced from Europe.

[Ill.u.s.tration: Fig. 52.]

=Winged Pigweed.= _Cycloloma atriplicifolium_ (Spreng.) Coulter. Seeds are likely to occur in either of three different guises depending upon the degree their ripeness or the amount of threshing to which they have been subjected. See the figure of this species. Seeds granular, circular, dull, jet-black, or gray in case the thin ovary remains, 1.3-1.7 mm. in diameter, lower face convex, the upper slightly convex if mature, with a slight notch on the rounded edge, the lower face bearing a slight curved groove, leading from the notch to near the center, the upper face with a light spot at the center. Introduced from western United States. A tumble weed, not common.

[Ill.u.s.tration: Fig. 53.]

=Russian Thistle.= _Salsola Kali tenuifolia_ G. F. W. Mey. This is not a thistle nor a cactus, but a pigweed. Concerning different stages of cleaning, note remarks above under Chenopodium alb.u.m (see the figures).

Seeds conical, the apex flattened or concave, both sides showing the long coiled embryo, light gray in color, about 2 mm. in diameter.

Introduced from northern Europe into the north west and from there into Michigan. Well advertised, though not of high rank as a weed in this state. A tumble weed.

AMARANTH FAMILY. AMARANTHACEAE.

[Ill.u.s.tration: Fig. 54.]

=Western Water Hemp.= _Acnida tuberculata Moq._ Seeds smooth, highly polished, brown to jet-black, double convex, nearly circular, with a slight notch at one edge, .6-.8 mm. in diameter, smaller, lighter colored, and thin margins less conspicuous than those found on the seeds of _Amaranthus circaezans_. There are three varieties with seeds much the same as these. Native of low ground in central and southern Michigan.

[Ill.u.s.tration: Fig. 55.]

=Prostrate Amaranth.= _Amaranthus blitoides_ S. Wats. Seeds smooth, highly polished, jet-black, double convex, nearly circular, with a slight notch at one edge, 1.4-1.5 mm. in diameter. Introduced from west of the Rocky Mountains. It thrives on sandy and gravelly banks. Margin of this seed is less p.r.o.nounced than in either of the other three noticed above. Found almost everywhere in fields of Michigan. Introduced from tropical America. Very common in annual hoed crops.

[Ill.u.s.tration: Fig. 56.]

=Tumble weed.= _Amaranthus graecizans_ L. Seeds smooth, highly polished, jet-black, double convex, nearly circular with a slight notch at one edge, .7-1 mm. in diameter. Compare with _Acnida_. Introduced from tropical America. It needs sand or gravel.

[Ill.u.s.tration: Fig. 57.]

=Slender Pigweed.= _Amaranthus hybridus_ L. (_A. chlorostachys_). Seeds smooth, highly polished, jet-black, double convex, broadly ovate, with a slight notch at the narrow extremity, 1.1-1.4 mm. long. Distinguished from the preceding species by having a seed ovate instead of circular.

Introduced from tropical America. Not abundant.

[Ill.u.s.tration: Fig. 58.]

=Rough Pigweeds.= _Amaranthus retroflexus_ L. Sometimes incorrectly called red-root. Seeds smooth, highly polished, jet-black, double convex, broadly ovate, with a slight notch at the narrow end, .9-1.2 mm.

long. The seeds of this and the next preceding are ovate, while those of the first two are very nearly circular. When seen edgewise, the hem-like margin of this seed is less prominent then in either of the preceding three noticed above. Found almost everywhere in annual crops.

Introduced from tropical America.

KNOTWEED FAMILY. ILLECEBRACEAE.

[Ill.u.s.tration: Fig. 59.]

=Knawel.= _Scleranthus annuus_ L. As the seed is single for each flower, it is unnecessary for the ovary to open; the small, hardened, ten-angled calyx with its five thick lobes aid in protecting and distributing the seed within. The seed is seldom seen. Calyx straw colored, obovoid, 2 mm. long besides the five spreading, membranaceous lobes, which are nearly as long. A low spreading plant, resembling some kinds of chickweed.

AIZOACEAE.

[Ill.u.s.tration: Fig. 60.]

=Carpet-Weed.= _Mollugo verticillata_ L. Seeds orange-red, shining, flattened, kidney-shaped or ovoid, .4-.6 mm. long, concave on the thinner edge from which protrudes a nipple-like point, a low central ridge pa.s.sing over the rounded edge. Native of warmer America. Needing sand.

PINK FAMILY. CARYOPHYLLACEAE.

[Ill.u.s.tration: Fig. 61.]

=c.o.c.kle.= _Agrostemma Githago_ L. Flowers rose-colored; pod erect, ovoid, about 16 mm. long; seeds dark brown to black, wedge-shaped-triangular, appearing as though the two extremities were bent together; surface covered with curved rows of conspicuous teeth, one side 3-3.5 mm. long. Introduced from Europe. In no sense a weed except in wheat fields.

[Ill.u.s.tration: Fig. 62.]

=Thyme-leaved Sandwort.= _Arenaria serpyllifolia_ L. Flowers white; seeds reddish brown to lead color, slightly flattened, circular to short-kidney-shaped. Each side covered with 4-5 curved rows of smooth, oval tubercles, giving the appearance of having two extremities bent together, about 5 mm. in diameter. Naturalized from Europe, delighting in light, poor soil. When well grown it becomes a tumbleweed.

[Ill.u.s.tration: Fig. 63.]

=Larger Mouse-ear Chickweed.= _Cerastium vulgatum_ L. Flowers white; pods cylindrical; seeds light-reddish yellow to dark reddish brown; slightly flattened, 4-sided, 2 of them straight, converging, one rounded, the other narrow and notched. Some of them ovoid, others nearly circular, covered with a few irregularly curved rows of tubercles, .4-.8 mm. in diameter. In large part introduced from Europe, though a native of this continent.

[Ill.u.s.tration: Fig. 64.]

=Bouncing Bet. Soapwort.= _Saponaria officinalis_ L. Flowers white; seeds dark lead-color, flattened, short-kidney-shaped to circular with notch on one side, 2 mm. across, more or less, with 6-7 curved rows of short, shiny tubercles. Naturalized from Europe, delighting in sandy soil.

[Ill.u.s.tration: Fig. 65.]

=Cow-herb.= _Saponaria Vaccaria_ L. Seed dull, jet-black, slightly roughened by great numbers of minute points, nearly spherical, 2.3 mm.

in diameter. An annual very troublesome in spring wheat. Introduced from Europe.

[Ill.u.s.tration: Fig. 66.]

=Sleepy Catch-Fly.= _Silene antirrhina_ L. Flowers pink; seeds lead-color, slightly flattened, circular to short-kidney-shaped, each side covered with 5-6 curved rows of pointed tubercles giving the appearance of having two blunt extremities bent together, .5-.7 mm.

across. Compare seeds with those of _Arenaria_ above described. When in flower, two of the upper internodes are glutinous. Only found on thin soil.

[Ill.u.s.tration: Fig. 67.]