Part 9

Sec. 1. ARABIS proper. _Seeds in one row in each cell, orbicular or nearly so, more or less wing-margined; cotyledons strictly accumbent._

[*] _Low, chiefly biennials, diffuse or spreading from the base._

1. A. Ludoviciana, Meyer. Nearly glabrous, often annual; leaves all pinnately parted into oblong or linear few-toothed or entire divisions, those of the lower leaves numerous; pedicels very short; flowers small, white; pods rather broadly linear, spreading, flat; seeds winged.--Open grounds, Va. to Mo., and southward.

[*][*] _Erect and simple leafy-stemmed biennials, with simple leaves, white or whitish flowers, narrow but flattened ascending or erect pods, and nearly wingless seeds._

2. A. patens, Sulliv. Downy with spreading hairs, erect (1--2 deg. high); stem-leaves oblong-ovate, acutish, coarsely toothed or the uppermost entire, partly clasping by the heart-shaped base; petals (bright white, 4'' long) twice the length of the calyx; _pedicels slender, spreading; pods spreading or ascending, tipped with a distinct style_.--Penn. to central Ohio and southward; Minn. April, May.

3. A. hirsuta, Scop. Rough-hairy, sometimes smoothish, strictly erect (1--2 deg. high); stem-leaves oblong or lanceolate, entire or toothed, partly clasping by a somewhat arrow-shaped or heart-shaped base; petals (greenish-white) small, but longer than the calyx; _pedicels and pods strictly upright; style scarcely any_; immature seeds somewhat 2-rowed.--Rocks, common, especially northward. May, June. (Eu.)

[*][*][*] _Erect and simple leafy-stemmed biennials (1--3 deg. high), with small whitish flowers, recurved-spreading or pendulous flat pods (3--4' long), and broadly winged seeds, their stalks adherent to the partition; root-leaves rarely lyrate._

4. A. laevigata, Poir. _Smooth_ and glaucous, upright; _stem-leaves partly clasping_ by the arrow-shaped base, lanceolate or linear, sparingly cut-toothed or entire; petals scarcely longer than the calyx; _pods long and narrow, recurved-spreading_ on ascending or merely spreading pedicels.--Rocky places, Maine to Minn. and southward. May.

5. A. Canadensis, L. (SICKLE-POD.) Stem upright, smooth above; _stem-leaves pubescent, pointed at both ends_, oblong-lanceolate, sessile, the lower toothed; petals twice the length of the calyx, oblong-linear; _pods very flat, scythe-shaped, hanging_ on rough-hairy pedicels (2'' wide).--Woods and ravines; not rare, especially westward. June--Aug.

Sec. 2. TURRITIS. _Seeds not so broad as the partition, in two more or less distinct rows in each cell, at least when young; strict and very leafy-stemmed biennials; cauline leaves partly clasping by a sagittate base. (Our species very glabrous, except the mostly hirsute base of the stem and the lower leaves.)_

6. A. perfoliata, Lam. (TOWER MUSTARD.) Tall (2--4 deg. high), _glaucous_; stem-leaves oblong or ovate-lanceolate, entire; _petals yellowish-white, little longer than the calyx; pods very narrow_ (3' long) _and pedicels strictly erect_; seeds marginless; cotyledons often oblique.--Rocks and fields, N. Eng. to Minn. (rare), north and westward. (Eu.)

7. A. confinis, Watson. Scarcely glaucous, 1--3 deg. high; pubescence below finely stellate; _stem-leaves lanceolate or oblong-linear_, entire (1--2' long), with narrow auricles, or the lowest spatulate and toothed; _petals white or rose-color, fully twice the length of the calyx_; pedicels and flat _pods loosely erect, or ascending, or even spreading_; seeds wing-margined, when mature little narrower than the partition. (A. Drummondii, _Man._)--From the lower St. Lawrence to Minn., south to Conn., N. Y., and Ill.--Pods 21/2--31/2' long, or in a var. (T. brachycarpa, _Torr. & Gray_) only 1--2' long.

Sec. 3. PSEUDARABIS. _Seeds oblong or elliptical, very small, wingless, in one row; cotyledons often more or less oblique. Biennial or perennial, branching from the base._

8. A. lyrata, L. Mostly glabrous, except the _lyrate-pinnatifid root-leaves_; stem-leaves scattered, spatulate or linear with a tapering base, sparingly toothed or entire; _petals white_, much longer than the yellowish calyx; pods long and slender, flat, ascending or spreading.--On rocks or sandy shores, New Eng. to Ky. along the mountains, Minn., and northward. April--July.--Usually biennial, but southward in the mountains decidedly perennial.

9. A. dentata, Torr. & Gray. Roughish pubescent, slender (1--2 deg. high); _leaves oblong_, very obtuse, unequally and sharply toothed; those of the stem _numerous, half-clasping and eared_ at the base, of the root broader and tapering into a short petiole; petals (whitish) scarcely exceeding the calyx; _pods widely spreading, very slender, short-stalked; style scarcely any_.--N. Y. to Mich., Minn., and southward. May, June.

6. DRABA, Dill. WHITLOW-GRASS.

Pod oval, oblong, or even linear, flat; the valves plane or slightly convex; the partition broad. Seeds several or numerous, in 2 rows in each cell, marginless. Cotyledons accumbent. Filaments not toothed.--Low herbs with entire or toothed leaves, and white or yellow flowers; pubescence often stellate. (Name from [Greek: dra/be], applied by Dioscorides to some cress; meaning unknown.)

Sec. 1. DRABAEA. _Petals not notched or cleft; perennial or biennial, leafy-stemmed, flowers white, pods twisted when ripe._

1. D. ramosissima, Desv. _Diffusely much branched_ and forming many radical tufts, perennial (5--8' high), pubescent; _leaves laciniate-toothed_, linear-lanceolate, the lower oblanceolate, racemes corymbosely-branched; _pods hairy_, oval-oblong or lanceolate (2--5'' long), on slender spreading pedicels, tipped with a _long style_.--Cliffs, Harper's Ferry, Natural Bridge, etc., Va., to Kentucky River, and southward. April, May.

2. D. incana, L. _Hoary-pubescent_, biennial or somewhat perennial, the radical tuft seldom branching; leaves oblanceolate or the cauline lanceolate to ovate, few-toothed or entire; _pods oblong to lanceolate, usually acute and straight, often pubescent_, on short erect pedicels; style very short or none.--Dry rocks, Willoughby Mountain, Vt.; also northward and far westward. (Eu.)

Var. arabisans, Watson. Caudex much branched; pod glabrous, acuminate or acute, twisted, beaked with a longer distinct style. (D. arabisans, _Michx._)--N. Vt. to western N. Y. and the shores of the upper lakes.

Sec. 2. DRABELLA. _Winter annuals; leafy stems short; flowers white (yellow in n. 5); style none. (Leaves oblong or obovate, hairy, sessile.)_

3. D. Caroliniana, Walt. Small (1--5' high); leaves obovate, entire; peduncles scape-like; petals usually twice the length of the calyx; _raceme short or corymbose in fruit_ (1/2--1' long); _pods broadly linear, smooth_, much longer than the ascending pedicels.--Sandy and waste fields, E. Mass. to Minn., and southward. March--May.--Petals often wanting in the later racemes, especially in the var. MICRANTHA, Gray, with minutely rough-hairy pods, which is found with the other, westward.

4. D. cuneifolia, Nutt. Leaves obovate, wedge-shaped, or the lowest spatulate, toothed; _raceme somewhat elongated in fruit_ (1--3'), at length equalling the naked peduncle; petals emarginate, much longer than the calyx; _pods oblong-linear, minutely hairy, longer than the horizontal pedicels_.--Grassy places, Ill. to E. Kan., and southward. March, April.

5. D. brachycarpa, Nutt. Low (2--4' high), minutely pubescent; _stems leafy_ to the base of the dense at length elongated raceme; leaves narrowly oblong or the lowest ovate (2--4'' long), few toothed or entire; flowers small; _pods smooth, narrowly oblong, acutish_ (2'' long), _about the length of the ascending or spreading pedicels_.--Dry hills, Ill., Ky., Va. (_A. H. Curtiss_), and southward. April.--Petals sometimes minute, sometimes none.

6. D. nemorosa, L. Leaves oblong or somewhat lanceolate, more or less toothed; _racemes elongated_ (4--8' long in fruit); petals emarginate, small; _pods elliptical-oblong, half the length of the horizontal or widely-spreading pedicels_, pubescent or smooth.--Fort Gratiot, Mich., N. Minn., and westward. (Eu.)

Sec. 3. EROPHILA. _Petals 2-cleft. (Annual or biennial; flowers white.)_

D. VERNA, L. (WHITLOW-GRASS.) Small (scapes 1--3' high); leaves all radical, oblong or lanceolate; racemes elongated in fruit; pods varying from round-oval to oblong-lanceolate, smooth, shorter than the pedicels.--Sandy waste places and roadsides. April, May. (Nat. from Eu.)

7. ALYSSUM, Tourn.

Pod small, orbicular, with only one or two wingless seeds in a cell; valves nerveless, somewhat convex, the margin flattened. Flowers yellow or white. Filaments often toothed. Cotyledons accumbent. (Greek name of a plant reputed to check the hiccup, as the etymology denotes.)

A. MARITIMUM, L. (SWEET ALYSSUM), with green or slightly hoary linear leaves, honey-scented small white flowers, and 2-seeded pods, commonly cult., begins to be spontaneous southward. (Adv. from Eu.)

A. CALYCINUM, L., a dwarf hoary annual, with linear-spatulate leaves, pale yellow or whitish petals little exceeding the persistent calyx, and orbicular sharp margined 4-seeded pod, the style minute, occurs occasionally in grassland. (Adv. from Eu.)

8. LESQUERELLA, Watson.

Pod mostly globular or inflated, with a broad orbicular to ovate hyaline partition nerved to the middle, the hemispherical or convex thin valves nerveless. Seeds few or several, in 2 rows, flat. Cotyledons accumbent. Filaments toothless.--Low herbs, hoary with stellate hairs or lepidote. Flowers mostly yellow. (Named for _Leo Lesquereux_.)

1. L. globosa, Watson. Minutely hoary all over; stems spreading or decumbent from an annual or biennial root; leaves oblong or lanceolate with a tapering base, repand-toothed or nearly entire; raceme at length elongated, with filiform diverging pedicels; petals light yellow; style filiform, much longer than the small globose, acutish, about 4-seeded pod; seeds marginless. (Vesicaria Shortii, _Torr._)--Rocky banks, Ky. to Tenn. and Mo. May, June.

2. L. gracilis, Watson. Annual, slender; pubescence very fine; leaves narrowly oblanceolate; pods glabrous, suberect on ascending or curved pedicels, stipitate; style long. (Vesicaria gracilis, _Hook._)--S. Kan. to Tex.

3. L. Ludoviciana, Watson. Biennial or perennial; pubescence compact; leaves linear-oblanceolate, mostly entire; pods pubescent, pendulous on recurved pedicels; style long. (Vesicaria Ludoviciana, _DC._)--Minn. to Neb. and southwestward.

9. CAMELINA, Crantz. FALSE FLAX.

Pod obovoid or pear-shaped, pointed, flattish parallel to the broad partition; valves 1-nerved. Seeds numerous, oblong. Cotyledons incumbent. Style slender. Flowers small, yellow. (Name from [Greek: chamai/], _dwarf_, and [Greek: li/non], _flax_.)

C. SATIVA, Crantz. Annual; leaves lanceolate and arrow-shaped; pods margined, large. A weed in flax-fields, etc. (Adv. from Eu.)

10. SUBULARIA, L. AWLWORT.

Pod ovoid or globular, with a broad partition; the turgid valves 1-nerved. Seeds several. Cotyledons long and narrow, incumbently folded transversely, i.e., the cleft extending to the radicular side of the curvature. Style none.--A dwarf stemless perennial, aquatic; the tufted leaves awl-shaped (whence the name). Scape naked, few-flowered, 1--3' high. Flowers minute, white.

1. S. aquatica, L. Margin of lakes in Maine; Echo Lake, Franconia, N. H.; also in alpine regions of the western mountains. June, July. (Eu.)

11. NASTURTIUM, R. Br. WATER-CRESS.

Pod a short silique or a silicle, varying from oblong-linear to globular, terete or nearly so; valves strongly convex, nerveless. Seeds usually numerous, small, turgid, marginless, in 2 irregular rows in each cell (except in N. sylvestre). Cotyledons accumbent.--Aquatic or marsh plants, with yellow or white flowers, and commonly pinnate or pinnatifid leaves, usually glabrous. (Name from _Nasus tortus_, a convulsed nose, alluding to the effect of its pungent qualities.)

Sec. 1. _Petals white, twice the length of the calyx; pods linear; leaves pinnate._

N. OFFICINALE, R. Br. (TRUE WATER-CRESS.) Perennial; stems spreading and rooting; leaflets 3--11, roundish or oblong, nearly entire; pods (6--8'' long) ascending on slender widely spreading pedicels.--Brooks and ditches; escaped from cultivation. (Nat. from Eu.)

Sec. 2. _Petals yellow or yellowish, seldom much exceeding the calyx; pods linear, oblong, or even ovoid or globular; leaves mostly pinnatifid._

[*] _Perennial from creeping or subterranean shoots; flowers rather large, yellow._

N. SYLVESTRE, R. Br. (YELLOW CRESS.) Stems ascending; _leaves pinnately parted_, the divisions toothed or cut, lanceolate or linear; pods (1/2' long) on slender pedicels, linear and narrow, bringing the seeds into one row; _style very short_.--Wet meadows, Mass. to Va.; rare. (Nat. from Eu.)

1. N. sinuatum, Nutt. Stems low, diffuse; _leaves pinnately cleft_, the short lobes nearly entire, linear-oblong; pods linear-oblong (4--6'' long), on slender pedicels; _style slender_.--Banks of the Mississippi and westward. June.

[*][*] _Annual or biennial, rarely perennial (?), with simple fibrous roots; flowers small or minute, greenish or yellowish; leaves somewhat lyrate._

2. N. sessiliflorum, Nutt. Stems erect, rather simple; _leaves obtusely incised_ or toothed, obovate or oblong; _flowers minute, nearly sessile_; pods elongated-oblong (5--6'' long), thick; style very short.--W. Ill. to E. Kan., Tenn., and southward. April--June.

3. N. obtusum, Nutt. Stems much branched, diffusely spreading; _leaves pinnately parted or divided_, the divisions roundish and obtusely toothed or repand; _flowers minute, short-pedicelled; pods longer than the pedicels_, varying from linear-oblong to short-oval; style short.--With n. 1 and 2.

4. N. palustre, DC. (MARSH CRESS.) Stem erect; _leaves pinnately cleft or parted_, or the upper laciniate; the lobes oblong, cut-toothed; _pedicels about as long as the small flowers and mostly longer than_ the oblong, ellipsoid, or ovoid _pods_; style short.--Wet places or in shallow water; common. June--Sept.--Flowers only 1--11/2'' long. Stems 1--3 deg. high.--The typical form with oblong pods is rare. Short pods and hirsute stems and leaves are common. Var. HISPIDUM is a form with ovoid or globular pods. (Eu.)

Sec. 3. _Petals white, much longer than the calyx; pods ovoid or globular; leaves undivided, or the lower ones pinnatifid; root perennial._

5. N. lacustre, Gray. (LAKE CRESS.) Aquatic; immersed leaves 1--3-pinnately dissected into numerous capillary divisions; emersed leaves oblong, entire, serrate, or pinnatifid; pedicels widely spreading; _pods ovoid, 1-celled, a little longer than the style_.--Lakes and rivers, N. E. New York to N. J., Minn., and southwestward. July--Aug.--Near N. amphibium.

N. ARMORACIA, Fries. (HORSERADISH.) Root-leaves very large, oblong, crenate, rarely pinnatifid, those of the stem lanceolate; fruiting pedicels ascending; _pods globular_ (seldom formed); _style very short_. (Cochlearia Armoracia, _L._)--Roots large and long; a well-known condiment. Escaped from cultivation into moist ground. (Adv. from Eu.)

12. BARBAREA, R. Br. WINTER CRESS.

Pod linear, terete or somewhat 4-sided, the valves being keeled by a mid-nerve. Seeds in a single row in each cell, marginless. Cotyledons accumbent.--Mostly biennials, resembling Nasturtium; flowers yellow. (Anciently called the Herb of St. Barbara.)

1. B. vulgaris, R. Br. (COMMON WINTER CRESS. YELLOW ROCKET.) Smooth; lower leaves lyrate, the terminal division round and usually large, the lateral 1--4 pairs or rarely wanting; upper leaves obovate, cut-toothed, or pinnatifid at the base; pods erect or slightly spreading; or in var. STRICTA, appressed; in var. ARCUATA, ascending on spreading pedicels.--Low grounds and roadsides; apparently introduced, but indigenous from L. Superior northward and westward. (Eu.)

B. PRAECOX, R. Br. (EARLY WINTER C.), with 5--8 pairs of lateral lobes to the leaves, and longer pods on very thick pedicels,--yet probably only a variety of the other,--somewhat cultivated from N. Y. southward as a winter salad, under the name of SCURVY-GRASS,--is beginning to run wild. (Eu.)

13. HESPERIS, Tourn. ROCKET.

Pod linear, nearly cylindrical; stigma lobed, erect. Seeds in 1 row in each cell, oblong, marginless. Cotyledons incumbent.--Biennial or perennial, with serrate sessile or petiolate leaves, and large purple flowers. (Name from [Greek: e(spe/ra], evening, from the evening fragrance of the flowers.)

H. MATRONALIS, L. (DAME'S VIOLET.) Tall; leaves lanceolate, acuminate, mostly petiolate; pods 2--4' long, spreading.--Sparingly naturalized. (Nat. from Eu.)

14. ERYSIMUM, Tourn. TREACLE MUSTARD.

Pod linear, 4-sided, the valves keeled with a strong midrib; stigma broadly lobed. Seeds in 1 row in each cell, oblong, marginless. Cotyledons (often obliquely) incumbent.--Chiefly biennials, with yellow flowers; the leaves not clasping. Pubescence of appressed 2--3-parted hairs. (Name from [Greek: e)ry/o], _to draw blisters_.)

1. E. asperum, DC. (WESTERN WALL-FLOWER.) Minutely roughish-hoary; stem simple, leaves lanceolate to linear, entire or somewhat toothed; _pods nearly erect_ or widely spreading _on short pedicels, elongated_ (3--4' long), exactly 4-sided; stigma 2-lobed.--Ohio (on limestone cliffs) to Ill., Ark., Dak., and common westward. June, July.--Plant stout, 1--2 deg. high; the crowded bright orange-yellow flowers as large as those of the Wall-flower. Petals orbicular, on very slender claws.

2. E. cheiranthoides, L. (WORM-SEED MUSTARD.) Minutely roughish, branching, slender; leaves lanceolate, scarcely toothed; flowers small; _pods small and short_ (7--12'' long), very obtusely angled, ascending on slender _divergent pedicels_.--Banks of streams, Mass. to Penn., Minn., and northward. July. (Eu.)

3. E. parviflorum, Nutt. Stem erect, often simple; leaves linear-oblanceolate, entire or the lowest coarsely toothed; flowers small (3'' long); pods narrow, 1--21/2' long, ascending on short pedicels.--Minn. to Kan. and westward.

15. SISYMBRIUM, Tourn. HEDGE MUSTARD.

Pod terete, flattish or 4--6-sided, the valves 1--3-nerved; stigma small, entire. Seeds oblong, marginless, in 1 or 2 rows in each cell. Cotyledons incumbent. Calyx open.--Flowers small, white or yellow. Pubescence spreading. (An ancient Greek name for some plant of this family.) Ours are mostly annuals or biennials.

1. S. humile, Meyer. Perennial, branching from the base, sparingly pubescent, 6' high or less; leaves narrowly oblanceolate, mostly coarsely and sharply toothed; flowers white or rose-color; pods very narrow, subterete, 4--9'' long, ascending on short pedicels, beaked with a short style, seeds 1-ranked. (Arabis petraea, _Man._, not _Lam._)--Willoughby Mountain, Vt.; Canada and westward. (N. Asia.)

2. S. canescens, Nutt. (TANSY MUSTARD.) _Leaves 2-pinnatifid_, often hoary or downy, the divisions small and toothed; flowers yellowish, very small; pods in long racemes, oblong-club-shaped or oblong-linear, shorter than their mostly horizontal pedicels; _seeds 2-ranked_ in each cell.--Penn. and N. Y. to Lake Superior, thence southward and westward. June--Aug.

S. SOPHIA, L. A similar hoary species, with decompound leaves; pods slender, 6--15'' long, ascending; seeds 1-ranked.--Sparingly naturalized from Europe.

S. OFFICINALE, Scop. (HEDGE MUSTARD.) _Leaves runcinate_; flowers very small, pale yellow; _pods awl-shaped, close pressed_ to the stem, scarcely stalked.--Waste places. May--Sept.--An unsightly branched weed, 2--3 deg. high. (Nat. from Eu.)

S. THALIANA, Gaud. (MOUSE-EAR CRESS.) _Leaves obovate or oblong, entire_ or barely toothed; flowers white; pods linear, somewhat 4-sided, longer than the slender spreading pedicels.--Old fields and rocks, Mass. to Kan. April, May.--A span high, slender, branched, hairy at the base. (Nat. from Eu.)

S. ALLIARIA, Scop. Stout, erect; leaves reniform to ovate-cordate, coarsely repand-dentate; flowers white; pods tapering, 1--2' long, ascending on very stout spreading pedicels.--Near Georgetown, D. C. (Nat. from Eu.)

16. THELYPODIUM, Endl.

Pod terete or teretish; valves 1-nerved; stigma mostly entire. Seeds in 1 row in each cell, oblong, marginless. Cotyledons obliquely incumbent.--Stout biennials or perennials, with mostly large purplish or white flowers. Leaves or petioles often auricled at base. (Name from [Greek: the~lys], _female_, and [Greek: pou/s], _foot_, the ovary in some species being stipitate.)

1. T. pinnatifidum, Watson. Glabrous (1--3 deg. high), often branched above; root-leaves round or heart-shaped, on slender petioles; stem-leaves auricled, ovate-oblong and ovate-lanceolate (2--6' long), sharply and often doubly toothed, tapering to each end, the lower into a winged petiole, rarely bearing a pair or two of small lateral lobes; flowers purplish; pods 1--11/2' long, on short diverging pedicels, pointed by a short style. (Arabis hesperidoides, _Gray_.) Alluvial river-banks, Ohio to Minn., Mo., and southwestward. May, June.

17. BRASSICA (Brassica and Sinapis), Tourn.

Pod linear or oblong, nearly terete or 4-sided, with a stout 1-seeded beak or a rigid style; valves 1--5-nerved. Seeds globose, 1-rowed. Cotyledons incumbent, folded around the radicle.--Annuals or biennials, with yellow flowers. Lower leaves mostly lyrate, incised, or pinnatifid. (The Latin name of the Cabbage. Sinapis is the Greek [Greek: si/napi], which is said to come from the Celtic _nap_, a turnip.)

B. SINAPISTRUM, Boiss. (or SINAPIS ARVENSIS, L., the English CHARLOCK), with knotty pods, fully one third occupied by a stout 2-edged beak (which is either empty or 1-seeded), the upper leaves barely toothed, is a noxious weed in grain-fields, from N. Eng. to Penn. and N. Y. westward. (Adv. from Eu.)

B. (or SINAPIS) ALBA. (WHITE MUSTARD.) Pods bristly, ascending on spreading pedicels, more than half its length occupied by the sword-shaped 1-seeded beak; leaves all pinnatifid; seeds pale. (Cult. and adv. from Eu.)

B. (or SINAPIS) NIGRA, Koch. (BLACK MUSTARD.) Pods smooth (1/2' long), 4-cornered (the valves only 1-nerved), erect on appressed pedicels forming a slender raceme, tipped with a stout persistent style; seeds dark brown, smaller and more pungent than in the last; lower leaves with a large terminal lobe and a few small lateral ones.--Fields and waste places. (Adv. from Eu.)

B. CAMPESTRIS, L., in the form of the RUTABAGA and the TURNIP, sometimes persists a year or two in neglected grounds.

18. CAPSELLA, Medic. SHEPHERD'S PURSE.

Pod obcordate-triangular, flattened contrary to the narrow partition; the valves boat-shaped, wingless. Seeds numerous. Cotyledons incumbent.--Annuals; flowers small, white. (Name a diminutive of _capsa_, a box.)

C. BURSA-PASTORIS, Moench. Root-leaves clustered, pinnatifid or toothed; stem-leaves arrow-shaped, sessile.--Waste places; the commonest of weeds. April--Sept. (Nat. from Eu.)

19. THLASPI, Tourn. PENNYCRESS.

Pod orbicular, obovate, or obcordate, flattened contrary to the narrow partition, the midrib or keel of the boat-shaped valves extended into a wing. Seeds 2--8 in each cell. Cotyledons accumbent. Petals equal.--Low plants, with root-leaves undivided, stem-leaves arrow-shaped and clasping, and small white or purplish flowers. (Ancient Greek name, from [Greek: thla/o], _to crush_, from the flattened pod.)

T. ARVENSE, L. (FIELD P. or MITHRIDATE MUSTARD.) A smooth annual, with broadly winged pod 1/2' in diameter, several seeded, deeply notched at top; style minute.--Waste places; rarely naturalized. (Nat. from Eu.)

20. LEPIDIUM, Tourn. PEPPERWORT. PEPPERGRASS.