CRUCIFERAE (MUSTARD FAMILY) 437 



or entire ; petals ichite, much longer than the yellowish calyx ; pods long and 

 slender, tiat, ascending or spreading; style slender, 0.8 mm. long. — On rocks 

 or sandy shores, w. N, E. to Man., and south vv. Apr.-July. — Usually biennial, 

 but southw. decidedly perennial. Var. occidextXlis Wats. Stigma sessile or 

 on a very short thick style (0.5 mm. or less in length). — Point Pelee, n. shore 

 of L. Erie ; Rocky Mts. to Alaska. (Kamchatka.) 



2. A. dentata T. & G. Roughish-pubescent, slender ; leaves oblong, very ob- 

 tuse, unequally and sharply toothed ; those of the stem numerous. half-cJaspiny 

 and auricJed, of the base broader and tapering into a short petiole ; petals 

 (whitish) scarcely exceeding the calyx ; pods u'idely spreading, very slendt^r, 

 short-stalked; style scarcely any. — N. Y. to Minn., Neb., and southw. May, 

 June. 



3. A. glabra (L.) Bernh. (Tower Mustard.) Tall (6-12 dm. high), ^?«?<- 

 cous ; stem-leaves oblong or ovate-lanceolate, entire ; petals yellovnsh white, little 

 longer than the calyx; pods very narroio (8 cm. long) and pedicels strictly erect ; 

 seeds marginless ; cotyledons often oblique. (^4. perfoliata Lam.) — Rocks ami 

 fields, N. B. to B. C, s. to N. J., Pa., Great Lake region, S. Dak., L^tah and 

 Cal. May-July. (Eu.) 



§ 2. TURRITIS [Dill.] Gaudin. Seeds not so broad as the partition, in tu'o 

 more or less distinct rows in each cell, at least ichen young ; strict and very 

 leafy-stemmed biennials; cauline leaves partly clasping by a sagittate base. 



Calyx essentially glabrous ; pods erect or loosely spreading. 



Pubescence of the basal rosettes none or sparse and of simple or of 2- 



pointed hairs attached by the middle 4.-4. Drummondi. 



Pubescence of the basal rosettes dense, stellate 5. A. hrachycarpa. 



Calyx stellate-pubescent ; pods deflexed or pendulous 6. A. Holhoellii. 



4. A. Drumm6ndi Gray. Nearly glabrous, somewhat glaucous, 3-9 dm. high ; 

 stem-leaves oblong or narrowly lanceolate, the basal spatulate-lanceolate ; pods 

 straightish, 3.5-10 cm. long, 1.3-2.3 mm. broad. (A. confinis Wats., in great 

 part.) — Rocky places, e. Que. to B.C., s. to N. S., s. N. E., N. Y., O., 111., 

 Utah, and Ore. 



Var. connexa (Greene) Eernald. Stout; pods 3-3.3 mm. wide. — Kiviere du 

 Loup, Que. ; and mts. of w. N. A. 



5. A. brachycarpa (T. & G.) Britton. Similar in stature and habit; bnsal 

 leaves densely pubescent v:ith '?>-pointed Jiairs, the cauline glabrous ; pedicels 

 icidely spreading ; pods 1.7-9 cm. long, 1-2 mm. broad, widely spreading. {A. 

 co?i^?izs Wats., in part ; Turritis brachycarpa T. & G.) — Sandy woods, rocky 

 banks, etc., e. Que, to Sask. and Assina., s. to N. B., n. Vt., N. Y. , Great Lake 

 region. Col., etc. 



6. A. Holboellii Horn em. Stems 1-several, 2-9 dm. high, leafy, somewhat 

 closely stellate-pubescent at the base, glabrous or glabrate above ; pedicels soon 

 deflexed ; petals pink or pinkish. 7-10 mm. long; pods 4-8 cm. long, 1.5-2.5 

 mm. broad, blunt, secund and strongly dejlered. — Rocky (calcareous) or sandy 

 places, e. Que. ; Thunder Baj", L. Huron (^]Mieeler) to the mts. of B. C. and Cal. 

 (Greenl.) 



§ 3. ARABIS proper. Seeds in one row in each cell, orbicular or nearly so, 

 more or less vying -margined ; cotyledons strictly accumbent. 



* Low, chiefly biennials, diffuse or spreading from the base. 



7. A. virginica (L.) Trel. Nearly glabrous, often annual; leaves all pin- 

 nately 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. (A. ludoviciana Mey.) — Open 

 ground, Va. to Kan., and southw. Mar. -May. 



* * Erect leafy-stemmed biennials, with simple leaves, white or ichitish flowers, 

 narrow but flattened ascending or erect pods, and nearly wingless seeds. 



8. A. patens Sulliv. Downy with spreading hairs, erect (3-6 dm. high); 

 stem-leaves oblong-ovate, acutish, coarsely toothed or the uppermost entire, 



