Dicotyls or Exogoioiis Plants. 55 



Car-da-mi'-ne penn-syl-van'-i-ca Muhl. Bitter Cress. — Differs from the 

 last in being large and very leafy, often 2 ft. high; the leaf-segments 

 larger, narrowed rather than rounded at the base as in C. hirsuta, and 

 they have a decided tendency to be decurrent on the rachis, are thin- 

 tier and more lobed, and the pedicels somewhat spreading. 



Car-da-mi'-ne ar-e-nic'-o-la Britt. Bitter Cress. — This, much resemb- 

 ling the preceding two species, is much branched at base, the numer- 

 ous ascending or erect leafy stems ()-12 in. high; leaves nearly erect, 

 divided into linear or linear-oblong segments; fruiting pedicels as- 

 cending and the pods strictly erect. Grows in open, sandy, moist soil. 



7. Genus DEN-TA'-RI-A. — Pod lanceolate, flat, seeds in one row; 

 rootstocks long, horizontal, fleshy, of a pleasant pungent taste ; the 

 simple stems with 2 or '?> compound leaves ; flowers large, w'hite or 

 purple in a corymb or short raceme. 



Den-ta-ri'-a di-phyl'-la h. Pepper-Root; Toothwort. — Rootstock long 

 and continuous, toothed ; stem-leaves 2, leaflets rhombic-ovate or ob- 

 long-ovate. 



Den-ta-ri'-a la-cin-i-a'-ta Muhl. Pepper-Root. — Rootstock tuberous,/ 

 more or less monoliform, tubers deep-seated ; stem-leaves 3-parted, / 

 the lateral segments often 2-lobed, all broadly oblong to linear, more 

 or less toothed. 



8. Genus BUR'-SA. — Pod obcordate-triangular, flattened, flowers 

 small, white; raceme liecoming much elongated. ,-_, 



Bur'-sa bur'-sa-pas-to'-ris (L.) Weber. [Capsclla biirsa-pasforis^ nT'*^ 

 Moench.) Shepherd's Purse. — Root-leaves clustered, pinnatifid or 

 toothed, stem-leaves sagittate and clasping. 



9. Genus DRA'-BA. — Pod oval, oblong or even linear, flat; seeds 

 in 2 rows in each cell; low plants with entire or toothed leaves, and 

 white flowers; pubescence often stellate. 



Dra'-ba in-ca'-na ar-a-bi'-sans (Mx.) Wats. Draba. — Hoary-pubescent, 

 leafy-stemmed ; leaves oblanceolate or the cauline ones lanceolate to 

 ovate ; pod glabrous, acuminate or acute, twisted, beaked with a dis- 

 tinct style. 



Dra'-ba car-o-li-ni-a'-na Walt. Draba. — Small, 1-5 in. high; leaves 

 obovate, entire; pods broadly linear, smooth, much longer than the as- 

 cending pedicels ; raceme short or corymbous in fruit. 



