CL. XV.] TETRAD YNAMIA SILIQUOSA. 273 



foot high : leaves heart-shaped at the base, with short, bristly hairs, 

 the uppermost becoming oblong bracteas : flowers pale-yellow : pods 

 thickened at the edges. Biennial: flowers in May : grows on old walls, 

 but is not indigenous : rare. Eng. Bot. vol. iii. pi. 178. Eng. Fl. vol. iii. 

 p. 214. 967. 



17. TURRl'TIS. TOWER MUSTARD. 



Calyx of four oblong, converging, erect, deciduous leaves, two 

 opposite ones slightly protuberant at the base. Petals inversely 

 egg-shaped, undivided, erect. Filaments thread-shaped, erect ; 

 anthers oblong. Germen linear, as long as the petals. Style very 

 short ; stigma obtuse. Pod linear, compressed, very long, its 

 valves straight, flat, with a prominent keel. Seeds very numerous, 

 arranged in two rows in each cell, crowded, egg-shaped, com- 

 pressed, slightly bordered. Name, from turris, a tower, which 

 the plant is supposed to resemble. 330. 



1. T. gldbra. Smooth Tower Mustard. Root-leaves toothed, rough, 



the rest entire, clasping the stem, smooth. Stem from two to three 



feet high, erect, simple, smooth : root-leaves oblong, nearly lyrate : flow- 

 ers numerous, corymbose, pale-yellow. Annual : flowers in May and 

 June : grows on banks and by road-sides in England : not common. 

 Eng. Bot. vol. xi. pi. 777. Eng. Fl. vol. iii. p. 215. 968. 



18. NASTURTIUM. CHESS. 



Calyx of four oblong, obtuse, spreading, deciduous leaves. 

 Petals inversely egg-shaped, undivided, spreading, with short 

 claws. Filaments awl-shaped, the two shorter each with a gland 

 at the base internally; anthers somewhat heart-shaped. Germen 

 cylindrical. Style erect, short, cylindrical} stigma obtuse, notched. 

 Pod nearly cylindrical, shortish ; its valves concave, without ribs 

 or keel. Seeds roundish, flattened, irregularly arranged, on slen- 

 der stalks. Name from nasus tarsus, a convulsed or distorted 

 nose. 331. 



1. N.officindle. Common Water-cress. Leaves pinnate, with round- 

 ish heart-shaped, waved leaflets. Stems spreading, generally floating, 



branched, angular, leafy, smooth : leaves deep-green : flowers white. 

 Perennial : flowers in June and July : grows in rivulets, clear ditches, 

 and ponds : common. Eng. Bot. vol. xii. pi. 855 : Sisymbrium 'Nastur- 

 tium. Eng. FL vol. iii. p. 192. 969. 



2. N.sylvestre. Creeping Yellow-cress. Leaves pinnate, with ellip- 

 tical, deeply serrate leaflets; root creeping. Stems erect, a foot high, 



angular, furrowed, roughish : flowers numerous, small, gold-yellow, in 

 terminal clusters. Perennial : flowers from June to September : grows 

 in wet meadows and watery places : not common. Eng. Bot. vol.xxxiii. 

 pi. 2324 : Sisymbrium sylvestre. Eng. Fl. vol. iii. p. 193. 970. 



3. N. terrgstre. Annual Yellow-cress. Leaves pinnatifid, unequally 



toothed ; root tapering ; petals not longer than the calyx. Stem a 



foot high, branched : flowers very small, pale-yellow. Annual : flowers 

 from June to September : grows in watery places: frequent. Eng. Bot, 

 vol. xxv. pi. 1747 : Sisymbrium terrestre. Eng. Fl. vol. iii. p. 194. 971. 



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