CRUCIFERJE. (MUSTARD FAMILY.) 31 



pods ovoid, one-celled, a little longer than the style. 1J. (N. natans, ed. 1. N. natans, 

 var. Americanum, Cray. Armoracia Americana, Arn.) Lakes and rivers, 

 N. New Fork to Illinois and Kentucky. July. 



8. N. ARMOKACIA, Fries. (HORSERADISH.) Root-leaves very large, ob- 

 long, eremite, rarely pinnatifid ; those of the stem lanceolate ; fruiting pedicels 

 ascending; pods globular (seldom fonned) ; style very short. 1J. (Cochlearia 

 Armoracia, L.) Boots large and long ; a well-known condiment. Escaped 

 from cultivation into moist ground. (Adv. from Eu.) 



2. IOI>A]\THUS, Torr. & Gray. FALSE KOCKET. 



Pod linear, elongated, terete ; the valves nerveless. Seeds in a single row in 

 each cell, not margined. Cotyledons accumbent. Claws of the violet-purple 

 petals longer than the calyx. A smooth perennial, with ovate-oblong pointed 

 and toothed leaves, the lowest sometimes lyrate-pinnatifid, and showy flowers in 

 paniclcd racemes. (Name from 10)8775, violet-colored, and avQos, flower.) 



1. I. liespeiidoides, Torr. & Gray. (Hesperis pinnatifida, Michx.) 

 Banks of rivers, west of the Alleghanies. May, June. Stem l-3 high. 

 Petals 5" long, spatulate. Pods 1' to nearly 2' long, somewhat curved upwards. 



3. I, EAV EN WORT HI A, Torr. LEAYENWORTHIA. 



Pod linear or oblong, flat ; the valves nerveless, but minutely reticulate- 

 veined. Seeds in a single row in each cell, flat, surrounded by a wing. Em- 

 bryo straight ! or the short radicle only slightly bent in the direction which if 

 continued would make the orbicular cotyledons accumbent. Little biennials or 

 hyemal annuals, glabrous and stemless, with lyrate root-leaves and short one- 

 few-flowered scapes. (Named in honor of Dr. M. C. Leavenworth, the discoverer 

 of one species.) 



1. It. MicllStikxii, Torr. Scapes one-Jlowered ; petals white or purplish, 

 yellowish towards the base. (Cardamine uniflora, Michx.} On flat rocks, 

 Southeastern Kentucky (also Tennessee and Alabama, whence Prof. Hatch scuds 

 it with purple flowers). March, April. 



2. L. aiirea, Torr. Scapes 1 -8-flowered; petals yellow, larger than in the 

 other (perhaps not distinct). With No. 1, and southwestward. 



4. I>E]VTARIA, L. TOOTHWORT. PEPPER-ROOT. 



Pod lanceolate, flat, as in Cardamine, but broader. Seed-stalks broad and 

 flat. Perennials, with long, horizontal, fleshy, sometimes interrupted, toothed 

 rootstocks of a pleasant pungent taste ; the low simple stems bearing 2 or 3 

 petioled compound leaves about the middle, and terminated by a single raceme 

 of large white or purple flowers. (Name from dens, a tooth.) 



1. D. <lij>liy!Ia, L. Rootstock long and continuous, toothed ; stem-kaves 2, 

 similar to the radical ones, close together, of 3 rhombic-ovate coarsely toothed 

 leaflets. Rich woods, Maine to Kentucky. May. Rootstocks 5' -If)' long, 

 crisp, tasting like Water-Cress. Flowers white. 



