ceuciferje. (mustard family.) 65 



§ 3. Petals white, much longer thantke calyx: pods ovoid or globular : leaves undivided, 

 or the lower ones pinnatifid : root perennial. (Armoracia.) 



7. N". lactistre, Gray, Gen. 111. 1, p. 132. (Lake Ceess.) Aquatic; 

 immersed leaves 1 - 3-pinnately dissected into numerous capillary divisions ; 

 emersed leaves oblong, entire, serrate, or pinnatifid ; pedicels widely spreading ; 

 pods ovoid, one-celled, a little longer than the style. (N. nataus, var. Americanum, 

 Gray. Armoracia Americana, Arn.) — Lakes and rivers, N. E. New York to 

 Illinois and south westward. July - Aug. — Near N. amphibium. 



8. N. AkmouAcia, Fries. (Hoksekadish.) Root-leaves very large, ob- 

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

 ascending; pods globular (seldom formed) ; style very short. (Cochleiria Armo- 

 racia, L.) — Boots large and long ; — a well-known condiment. Escaped from 

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



2. LEAVENWORTHIA, Torr. Leavenwortiiia. 



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

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

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

 if continued would make the orbicular cotyledons accumbent. — Little biennial 

 or hyemal annuals, glabrous and stemless, with lyrate rooMeaves and short 

 one - few-flowered scapes. (Named in honor of the late M. C. Leavenworth.) 



1. L. Michaiixii, Torr. — Onflat rocks and barrens, S.E.Kentucky and 

 southwestward : rare. March - May. — Scapes 2' - 4' high. Petals purple, 

 rose color, or nearly white, with a golden yellow or yellowish base, or rarely 

 yellow throughout? (L. aurea, Torr.), cuneate-obcordate or emarginate; the 

 flowers rather large for the size of the plant. 



3. DENTABIA, L. Toothwokt. Peppee-eoot. 



^Pod lanceolate, flat, as in Cardamine, but broader. Seedstalks broad and 

 flat. Cotyledons petioled, their margins somewhat infolding each other. — 

 Perennials, with long, horizontal, fleshy, sometimes internipted, scaly or toothed 

 rootstocks, of a pleasant pungent taste ; the simple stems leafless below, bear- 

 ing 2 or 3 petioled compound leaves about the middle, and terminated by a 

 single corymb or short raceme of large white or purple flowers. (Name from 

 dens, a tooth.) 



1. D. diph^Ua, L. Rootstock long and continuous, toothed ; stem-leaves 2, 

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

 leaflets ; petals white. — Rich woods, Maine to Kentucky. May. — Rootstocks 

 5' - 10' long, crisp, tasting like Water-Cress. 



2. D. maxima, Nutt. Rootstockintemipted,formingastring of thick toothed 

 tubers; stem4eaves (2-7) mostly 3 and alternate; leaflets 3, ovate, obtuse, coarsely 

 toothed and incised, often 2 - 3-cleft ; petals pink. (D. laciniata, var. d, Torr. 

 Sf Gr.) — Northern New Tork (Watertown, Crawe; tJtica, Paine) to Penn. : 

 rare. May. — Seldom taller, but the leaves often smaller, than in No. 1. 



3. D. heteroph^lla, Nutt Rootstock a chain of 2 or 3 narrow-oblong and 

 obscurely toothed tubers ; stem-leaves 2 or 3, alternate (rarely opposite), divided into 



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