Fig 212.

Fig 212.>Dandelion. Taraxacum officinale Weber. Taraxacum Taraxacum (L.) Karst.

Dandelion. Taraxacum officinale Weber. Taraxacum Taraxacum (L.) Karst. Flowers yellow; achenes dull light to dark brown, flattened oblanceolate, thread-like beak two to three times as long as the achene, the stout colored beak 0.5 mm. long. The most conspicuous character of the achenes lies in the barb-like-toothed edges and ridges of each of the similar 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.

Fig 213.

Fig 213. Salsify. Oyster-Plant. Tragopogon porrifolius L.

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.

Fig 214.

Fig 214. American Cocklebur. Xanthium Canadensis Mill.

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.

Fig 215.

Fig 215. Spiny Clotbur. Xanthium spinosum L.

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.

Name,----Page

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.

A-cu´min-ate, ending in a prolonged tapering point.

A-nat´ro-pous, a name applied to an ovule or seed which grows so that the funiculus coheres to the whole length forming a raphe along the edge bringing the hilum near the micropyle while the chalaza is at the other extremity.

A´pex, the tip or growing point of an organ.

Awn, a bristle-shaped appendage.

Barbed, furnished with rigid points or short bristles, usually reflexed like the barb of a fish-hook.

Car´un-cle, an excrescence or protuberance near the hilum of a seed.

Co´ma, a tuft of hair on a seed.

Del´toid, shaped like the Greek letter delta; triangular.

El-lip´tic-al, oblong and rounded at the ends; longer than oval.

Em´bry-o, the little plant forming a part of the seed, usually consisting of caulicle, one or more cotyledons and a plumule.

Fe´male flow´er, one having pistils only, but no stamens; pistillate flower.

Fer´tile, producing fruit, or reproductive bodies of any kind.

Flo´ret, a single flower of a head or cluster, especially in Compositae.

Glume, one of the outer floral envelopes in grasses or sedges. The term as now used includes the bracts (empty glumes) which subtend a spikelet and the lower of the two bracts subtending the individual flower (flowering or floral glume, lemma).

Grain, the caryopsis or fruit of Gramineae; any small seed.

Has´tate, like the head of a halberd—applied to leaves which have a spreading lobe on each side of the base.

Hi´lum, the scar or point of attachment of a seed.

In-cum´bent, leaning or lying upon; applied to cotyledons when the caulicle is folded against the track of one of them, shown as [Symbol: || o].

In-dig´e-nous, native and original to the region.

In´vo-lu-cre, a set of bracts immediately subtending a flower or inflorescence.

Keel, the joined pair of petals in a papilionaceous corolla; a projecting ridge along the back of an organ.

Lan´ce-o-late, tapering abruptly towards the base and gradually towards the apex, like the head of a lance.

Lin´e-ar, very narrow with the margins parallel or nearly so.

Ob-lan´ce-o-late, lanceolate in form, but tapering toward the base more than toward the apex.

Ob´long, longer than wide with nearly parallel sides. Compare Oval.

Ob-o´vate, a flat body broader toward the apex than the base. See Ovate.

Ob-o´void, a solid body broader towards the apex than the base. See Ovoid.

Ob-tuse´, having a rounded end or apex; blunt.

O´val, about twice as long as broad, with regular curved outlines, broadly elliptical.

O´vate, like a longitudinal section of an ordinary hen's egg, with the attachment, if any, at the broad end.

O´void, the shape of a hen's egg and attached, if at all, at the large end.

Pa´le-a, Pa´let, the upper bract which with the floral glume incloses the flower in grasses.

Pu-bes´cent, clothed with soft and rather short hairs.

Ra´phe, the adherent funiculus connecting the hilum and chalaza in anatropous or amphitropous ovules or seeds.

Re-tic´u-late, in the form of network.

Root, the descending axis which is destitute of leaves or nodes.

Root stock, rhizome, a stem usually subterranean and more or less thickened, producing young branches.

Spike´let, a small or secondary spike, as found in grasses.

Ster´ile, not fertile.

Stri´ate, striped with parallel ridges and grooves.

Trun´cate, terminating abruptly, as though cut off or flattened at the end. Compare Premorse and Succise.

Tu´ber-cle, a swollen part or a root due to bacteria. Usually applies to such as possess the power to fix nitrogen; a little tuber.