464 FLORA. 



Arabis lyruta occidentals S. Wats. Valves of the pod thin, faintly nerved; stigma 

 sessile or very nearly so. Lake 1 .tie ; Br. Col. to Alaska. 



3. Arabis arenicola (Richards.) Gelert Arctic Rock cress. (I. F. f. 1773.) 

 Perennial, pubescent below, or glabrous; stems diffuse or ascending, O.7-1.5 dm. 

 long. Leaves spatulate or oblong, nearly entire. 8 16 mm. long, the lower petioled; 

 flowers purplish or white, about 6 mm. broad; style very short; pods linear, flat, 

 at length drooping, 1.5-2.5 cm. long, rather more than 1 mm. wide, the valves 

 very faintly nerved; seeds in 2 incomplete rows in each cell; cotyledons imper- 

 fectly accumbent. Greenland and Lab. to Hudson Bay and the N. W. Terr. 

 Summer. [A. kumifusa S. Wats.] 



4. Arabis dentata T. & G. Toothed Rock-cress. (I. F. f. 1774.) Slender, 

 ^-6 dm. high, finely rough -pubescent. Basal leaves with margined petioles, obovate, 

 dentate, 5-10 cm. long, obtuse ; stem-leaves sessile, clasping by an auricled base, 

 dentate ; pedicels 2-4 mm. long; flowers greenish white. 2-4 mm. broad, the petals 

 hardly exceeding the calyx ; pods narrowly linear, 2-3 cm. long, spreading ; style 

 almost none. W. N. Y. to Minn., Tenn., Mo. and Kans. April -June. 



5. Arabis alpina L. Alpine Rock cress. (I. F. f. 1775.) Densely and 

 finely pubescent, 1-3 dm. high. Basal leaves 2-5 cm. long, obovate or spatulate, 

 obtuse, dentate, on margined petioles ; stem-leaves ovate, sessile, clasping by an 

 auricled base, dentate; flowers white, 4-6 mm. broad; petals much exceeding the 

 calyx; pedicels 8 mm. long in fruit; pods 2-4 cm. long, curved upward, narrowly 

 linear, 2 mm. broad. Quebec to Lab. and Alaska. Europe and Asia. Summer. 



6. Arabis patens Sulliv. Spreading Rock-cress. (I. F. f. 1776.) Erect, 

 3-6 dm. high, pubescent at least below. Basal leaves dentate, 2-8 cm. long, on 

 margined petioles ; stem-leaves 2-5 cm. long, ovate or oblong, acute or acutish, 

 sessile, dentate or nearly entire, partly clasping; pedicels 12-16 mm. long in fruit; 

 pods 2-4 cm. long, 1 mm. broad, not appressed. E. Penn. to Minn., Ala. and Mo. 

 Summer. 



7. Arabis hirsuta (L.) Scop. Hairy Rock-cress. (I. F. f. 1777.) Stem 

 erect, 3-6 dm. high. Basal leaves with margined petioles, obovate or spatulate, 

 obtuse, dentate or repand, 2-5 cm. long ; stem-leaves sessile, clasping, lanceolate 

 or oblong ; pedicels nearly erect, 6-12 mm. long in fruit ; pods narrowly linear, 

 erect, 2-5 cm. long, about 1 mm. wide; seeds 1 -rowed, or when young obscurely 

 2-rowed, oblong or nearly orbicular. In rocky places, N. B. to Br. Col., Ga., Ariz, 

 and Cal. Also in Europe and Asia. May-Sept. 



8. Arabis laevigata (Muhl.) Poir. Smooth Rock cress. (I. F. f. 1778.) 

 Glaucous, glabrous, 3-9 dm. high. Basal leaves petioled, spatulate or obovate, 

 sharply dentate, 5-8 cm. long ; stem-leaves sessile, lanceolate, or the upper linear, 

 acute, clasping by an auricled or sagittate base ; pedicels 8-10 mm. long in fruit , 

 petals nearly twice the length of the calyx; pods 7-10 cm. long, 2 mm. wide, re- 

 curved-spreading ; seeds broadly winged; style almost none. In rocky woods, 

 Quebec to Minn., Kans., Ga. and Ark. April-May. 



Arabis laevigata laciniata T. & G. Stem-leaves deeply and narrowly laciniate-toothed 

 Kv. 



Arabis laevigata Biirkii Porter. Leaves linear or lanceolate, elongated, entire or 

 sparingly toothed, not auricled at the base; flowers one-half the size of the type; petals 

 equalling the sepals. Penn. to N. Car. 



9. Arabis Canadensis L. Sickle-pod. (I. F. f. 1779.) Stem 3-9 dm. 

 high, pubescent below. Basal leave- narrowed into a petiole, dentate or lyrately 

 lobed, 7-16 cm. long; stem-leave- sessile, lanceolate or oblong, narrowed at each 

 end, toothed, or the'upper entire, pubescent ; pedicels spreading or recurved and 

 8-12 mm. long in fruit ; petals twice as long as the calyx ; pods 5-9 cm. long, 

 3 mm. broad, scythe-shaped, pendulous : style almost none. In woods, Ont. to 

 N. II.. Ga.. Minn.. Kans, and Tex. [une Aug. 



10. Arabis brachycarpa (T. & G.) Britton. PURPLE Rock-cress. (I. F. f. 

 ,_) Glauco lly purplish, glabrous except at the base. 3-9 dm. high. 

 I leaves stellate-pubescent, obovate or spatulate. 2-8 cm. long, dentate, 



n irrowed into a petiole; stem-leaves sessile, auricled, lanceolate or oblong-linear, 

 entire or with a lew teeth: pedicels 6 10 mm. long in fruit; flower- white or pink, 

 8 mm. broad; petals twice the length of the calyx; pods narrowly linear, nearly 



