MUSTARD FAMILY 337 



ately toothed; pedicels short, in fruit scarcely more than 4 mm. long;, diverging 

 or reflexed; petals light yellow, not quite 1 mm. long; fruit 5-6 mm. long, shghtly 

 thicker at the base; style not 0.5 mm. long. Wet places, in the mountains: 

 Colo. Subalp. S. 



17. R. integra (Rydb.) Heller. Biennial, glabrous; stems few, strict, branched 

 above; stem -leaves spatulate or rhombic-spatulate, 1-2 cm. long, not auricled 

 at the base; petals 1.5 mm. long, scarcely exceeding the sepals; pedicels 1-3 mm. 

 long, ascending; pod about 8 mm. long, somewhat curved; style about 0.5 mm. 

 long. Roripa integra Rydb. Wet places, in the mountains: Utah. Mont. 

 Au. 



18. R. sessiliflora (Nutt.) Greene. Annual or biennial; stem usually erect, 

 branched, glabrous; leaves lobed or cleft, with rounded lobes, or merely coarsely 

 crenate; petals 1.5-2 mm. long; pedicels 1-2 mm., or sometimes almost none; 

 pod 6-12 mm. long, fully 2 mm. thick; beak short and thick. Nasturtium sessili- 

 florum Nutt. Wet places: 111.— Fla.— Tex.— Neb. Plain. Ap-S. 



16. SISYMBRIUM (Tourn.) L. Water-cress. 



Aquatic perennials, with floating or creeping stems, rooting at the nodes. 

 Leaves odd-pinnate. Flowers perfect, in racemes. Sepals equal at the base, 

 spreading during anthesis. Petals white, without nectaries. Pods cylindric; 

 valves 1-nerved. Styles slender; stigma 2-lobed. Seeds in 2 rows, turgid. 

 Cotyledons accumbent. 



1. S. Nasturtium-aquaticum L. Aquatic perennial; leaves pinnate, with 

 1-11 orbicular to oblong-lanceolate sinuate leaflets; sepals oblong, about 2 mm. 

 long; petals white, spatulate, about 4 mm. long; fruiting pedicels divaricate; 

 pod 1-2 cm. long, 3 mm. thick, somewhat curved; beak about 1 mm. long. In 

 water and mud: N.S. — Va. — Calif. — B.C.; Mex., W. Ind., S. Am.; nat. from 

 Eu. Plain— Subalp. My-S. 



17. TURRITIS L. Tower Mustard. 



Caulescent herbs, with partly clasping, auricled stem-leaves. Flowers in 

 elongate racemes. Sepals erect, two of them slightly saccate at the base. 

 Petals yellowish white, small. Pods erect, linear-cylindric, terete or slightly 

 flattened, 1-nerved and veined; stigma cupulate. Seeds flattened, partially 

 incumbent, i. e., radicle oblique. 



1. T. glabra L. Biennial; stem erect, 6-15 dm. high, hirsute below; basal 

 leaves oblanceolate, sinuately toothed or somewhat lyrate, hirsute-steUate, 

 5-15 cm. long; stem-leaves glabrous, lanceolate, sagittately clasping, 2-10 cm. 

 long; sepals and petals greenish white, 3 mm. long; pedicels erect, 4-12 mm. long; 

 pod erect, 4^10 cm. long, 1.5-2 mm. wude. Arabis perfoliata Lam. A. glabra 

 (L.) Bernh. Waste places: Que. — Pa. — Calif. — B.C.; nat. from Eu. Plain — 

 Submont. Ap-Au. 



18. ERYSIMUM L. Hedge Mustard. 



Annual caulescent herbs. Leaves alternate, pinnately lobed. Flowers 

 perfect, in racemes. Sepals subequal, ascending. Petals small, pale yellow. 

 Filaments unappendaged. Pod subulate, tapering from the base to the apex. 

 Style almost none; stigma 2-lobed. Cotyledons incumbent. Seeds in one row, 

 marginless. 



1. E. officinale L. Annual; stem branching, hirsute, at least below; leaves 

 hirsute, pinnatifid or the uppermost merely hastate; terminal lobes of the lower 

 leaves rounded and toothed, those of the upper lanceolate; petals pale yellow, 

 spatulate, 3 mm. long; pods erect, on very short pedicels, 1.5-2 cm. long, gla- 

 brous or pubescent. Sisymbrium officinale Scop. Waste places: N.S. — Fla. — 

 Calif. — B.C.; nat. from Eu. Plain — Submont. My-S. 



19. NORTA Adans. Tumble Mustard. 



Caulescent leafy annuals, with runcinately pinnatifid or toothed leaves, 

 pubescent with simple hairs. Flowers perfect, in elongate racemes. Sepals 

 15 



