Seeds of Michigan Weeds - LightNovelsOnl.com
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[Ill.u.s.tration: Fig. 166.]
=Moth Mullein.= _Verbasc.u.m Blattaria_ L. Flowers yellow; pod 6 mm.
diameter; seeds light to dark brown, .5-1 mm. long, columnar, lateral surface slightly angular and 6-sided, base truncate or obliquely so and broader than the rounded apex, thus somewhat thimble-shaped, each lateral face deeply pitted in longitudinal rows, the pits in contiguous rows, alternating. Introduced from Europe. A vile weed in meadows and pastures.
=Velvet-Leaved Mullein.= _Verbasc.u.m Thapsus_ L. Flowers yellow; pod 6 mm. high; seeds cannot be distinguished with certainty by means of the ordinary lens from those of moth mullein. The pitted surface seems to predominate in _Verbasc.u.m Blattaria_, while the grooved surface seems to be more common in the seeds of V. Thapsus. Introduced from Europe.
Common in thin pastures.
[Ill.u.s.tration: Fig. 167.]
=Wall Speedwell.= _Veronica arvensis_ L. Pods heart-shaped; seeds dull, light yellow, flattened, oval, .7-1.1 mm. long on one side appearing as though the two ends had been brought together by bending. From Europe.
[Ill.u.s.tration: Fig. 168.]
=Common Speedwell.= _Veronica officinalis_ L. Pods heart-shaped; seeds dull, pale yellow, flattened, broadly oval to broadly obovate, .8-1.2 mm. long, with a small scar near the middle of one side, from which extends a faint line (raphe) to one extremity. Appearing as though introduced.
[Ill.u.s.tration: Fig. 169.]
=Purslane Speedwell.= _Veronica peregrina_ L. Pods heart-shaped; seeds dull, light reddish yellow, flattened, oval to broadly obovate .5-.8 mm.
long, with a small scar a little above the middle of one side, from which extends a dark line (raphe) to one extremity. Most likely native to this country.
[Ill.u.s.tration: Fig. 170.]
=Thyme-leaved Speedwell.= _Veronica serpyllifolia_ L. Pods broadly heart-shaped; seeds pale yellow, a trifle darker than those of V.
officinalis, light, reddish yellow, in shape and markings much like those of V. peregrina, flattened, broadly oval to obovate .5-.7 mm.
long, with a small scar near the middle on one side, from which extends a dark line (raphe) to one extremity.
Apparently native to this country.
Seeds of the Veronicas are very difficult to distinguish from one another.
PLANTAIN FAMILY. PLANTAGINACEAE.
[Ill.u.s.tration: Fig. 171.]
=Sand Plantain.= _Plantago arenaria_ W. & K. Seeds dark amber brown, s.h.i.+ning, rounded on the back like the bottom of a shallow canoe, 2.5-3 mm. long, transverse groove around the middle of the back, opposite side with a groove extending lengthwise, about as wide as the ridge on either side of it; hilum in the middle of the groove. Found at Harrisville, Mich.
[Ill.u.s.tration: Fig. 172.]
=Large-bracted Plantain.= _Plantago aristata_ Michx. Seeds oval, dull, light to dark brown, 2.2-3 mm. long, shaped like a shallow, thick-walled canoe with ends rounded alike, outer face marked by a shallow, transverse groove at or near the middle, a white line marking the margin at the base on the canoe inside, two white-margined pits occupying the middle of the concave side. Introduced from the west in clover seeds, not yet common.
[Ill.u.s.tration: Fig. 173.]
=Rib-Gra.s.s. Narrow-leaved Plantain.= _Plantago lanceolata_ L. Seeds s.h.i.+ning, amber-colored to brown, oval, 2-2.5 mm. long, shaped like a shallow, thick-walled canoe with ends rounded alike, a dark scar occupying the middle of the narrow concave side, a faint, transverse groove across the convex side near the middle sometimes apparent. Often found mixed with clover seeds from which it is very difficult to separate. Introduced from Europe.
[Ill.u.s.tration: Fig. 174.]
=Broad-leaved Plantain.= _Plantago major_ L. Seeds, light to dark brown or very nearly black, 1-1.5 mm. long, slightly flattened, with acute edges very variable in shape, oval, oblong, rhomboidal and trapezoid, the surface roughened by slender, colored ridges, appearing under the lens as slightly wavy lines, radiating from the scar. The clear light green color of the lower end of the leaf-stem is an easy mark to distinguish this plant from another broad-leaved plantain, _P. Rugelii_ in which the base of leaf is red. Introduced from Europe. About door yards.
[Ill.u.s.tration: Fig. 175.]
=Rugel's Broad-leaved Plantain.= _Plantago Rugelii Decne._ Seeds dark brown to black, much like those of P. major, but larger, 1.5-2.5 mm.
long slightly flattened, with edges acute, very variable in shape, oval oblong, rhomboidal, surface minutely roughened and dull, but wholly without ridge or lines as in P. major. Native of this country. Lower end of leaf-stalk red, and not clear green as in P. major. A vile pest in clover fields.
MADDER FAMILY.
[Ill.u.s.tration: Fig. 176.]
=Blue Field Madder.= _Sherardia arvensis_ L. The parts often called seeds are in reality the half-fruits ripened, each one bearing at the apex three, white, pointed, persistent calyx lobes, the inner face showing a vertical groove, and in some of the fruits the calyx is broken off. Surface dull brown, clothed with small white hairs, obovoid, 2-2.5 mm. long. Introduced from Europe, not often found in the northern states.
TEASEL FAMILY. DIPSACACEAE.
[Ill.u.s.tration: Fig. 177.]
=Wild Teasel.= _Dipsacus sylvestris_ Huds. Achene brown, minutely hairy, 4 mm. long, oblong, square in cross-section, with four vertical ribs on the angles and four on the sides. Seed suspended, anatropous, supplied with endosperm. Introduced from Europe. A weed requiring two years from seed to seeding.
COMPOSITE FAMILY. COMPOSITAE.
[Ill.u.s.tration: Fig. 178.]
=Yarrow. Milfoil.= _Achillea Millefolium_ L. Flowers white; achenes white to gray, finely striate lengthwise, flattened, oblong, tapering at the lower end, straight or curved. 2-2.3 long. Most likely introduced from Europe.
[Ill.u.s.tration: Fig. 179.]
=Ragweed.= _Ambrosia artemisiifolia_ L. Achenes hard, straw-colored to light brown or black, top-shaped, broadly oval, 2.5-3 mm. long, besides the beak 1.5 mm. long, the sides irregularly ridged vertically, with 5-10 short teeth at the apex. Sometimes the hard covering is removed by a clover huller, exposing the naked seed. Native of the U. S.
[Ill.u.s.tration: Fig. 180.]
=Great Ragweed.= _Ambrosia trifida_ L. Achenes hard, brown, more or less mottled, top-shaped, 7-8 mm. besides the stout beak 2-3 mm. long, sides with 5 stout ridges terminating in 5 short teeth. Native to the United States. River bottoms, low land, sometimes 15 ft. high.
[Ill.u.s.tration: Fig. 181.]
=Corn Camomile=. _Anthemis arvensis_ L. Achenes very variable, creamy white to light brown, oblong, wedge-shaped in outline, circular to four-angled in cross-section, more or less ribbed lengthwise, a ripple-shaped scar at the narrow end; apex truncate with a minute projection in the center, often with a narrow ridge about the margin.
About 1.7 mm. long. Introduced from Europe. Seldom troublesome in Michigan.
[Ill.u.s.tration: Fig. 182.]
=May-weed. Dog's-Fennel.= _Anthemis Cotula_ L. Outer flowers white; achenes straw color to light brown, obovoid (large end uppermost) to oblong, circular in outline, 1.3-1.8 mm. long, with 10 warty ribs.
Introduced from Europe. Old roads and waste places.
[Ill.u.s.tration: Fig. 183.]
=Great Burdock.= _Arctium Lappa._ So far as I have seen the achenes of this species, when compared with A. minus, are darker colored, rather longer, the ribs more distinct.
=Smaller Burdock.= _Arctium minus_ Beruh. Possibly only a variety of _A.
Lappa_ L., but the prevailing plant in central Michigan. I see no way of distinguis.h.i.+ng the achenes of one from the other; but it makes little difference as one burdock is as bad as another.
