CLASS XV. ORDER II J DENTARIA. 921 



Perennial ; flowering in July and August. 



The whole plant, when bruised, has a very disagreeable odour and 

 acrid taste. It varies considerably in the stem being more or less 

 branched, and the leaves more or less cut in a pinnalifid or bi-pinnalifid 

 manner, with ovate, linear, entire or toothed lobes. It is much more 

 frequent on the Continent than with us, and grows abundantly on 

 many of the ruins and old walls of Rome. 



2. D. mura'lis, De Cand. (Fig. 1064.) Sand Biplotaxis, or Mustard. 

 Siliqua linear, smooth, erect, on long spreading pedicles; style short; 

 leaves obovate, peliolated, sinualed, the lower ones often sub-lyrato- 

 pinnatifid ; stems spreading, hairy below. 



De Cand. Prod. 1. p. 222.— Lindley, Synopsis, p. SS.-- Sisymbrium 

 murale, Linn.— English Botany, t. 1090.— Sinapis muralis, Br.— 

 English Flora, vol. iii. p. 224.— Hooker, British Flora, ed. 4. vol i. p. 

 257. 



Root tapering. Stem mostly branched from the base and spreading, 

 round, and more or less clothed with reflexed hairs. Leaves peliolated, 

 smooth, oblong, obovate, or broadly lanceolate, obtusely toothed, 

 sinuated irregularly, and the lower ones often somewhat lyrate, some- 

 times, though rarely, they are slightly hairy. Inflorescence a few 

 flowered sub-corymbose raceme, becoming much elongated after 

 flowering, pedicles long, slender, spreading. Cahjx of four oblong 

 spreading pieces. Petals four, ovate, tapering into a claw, pale lemon 

 colour. Fruit linear, spreading, smooth, sessile on the pedicle, the 

 valves with a prominent dorsal rib. Style short, crowned by the obtuse 

 somewhat dilated stigma, and more or less notched. Seeds ovate, dis- 

 posed in two rows, but often interrupted. 



Habitat.— Sandy places in the South and South-West of England; 

 the Jsle of Thanet, and Dumfermline, Scotland. 



Annual ; flowering in August and September. 



This is a variable looking species, both in size and the shape of its 

 leaves ; sometimes it is not more than a few inches high, and at others 

 more than two feet long, slender, and is more or less clothed with 

 bristly hairs. The leaves are variously and more or less deeply lobed 

 and toothed, and the teeth are obtuse, or acute. It is common on the 

 sea shore in various parts of the Continent. 



GENUS XXVIT. DENTA'RIA.— Linn. Coralroot. 

 Nat. Ord. Crucif'er^.- Juss. 

 Gen. Char. Siliqua linear, lanceolate, valves flat, ribless. Seeds 

 ovate, attached by a dilated cord. Cotyledons accumbent.— (See 

 Fig. 2, p. 872.)— Name from dens, a tooth ; so called on account 

 of the tooth-like scales on the roots. 



