CL. XV.] TETRAD YNAMIA SILIQTJOS A. 273 



About a 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. TURRI'TIS. TOWER MUSTARD. 



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

 two opposite ones slightly protuberant at the base. Petals in- 

 versely 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, compressed, 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 : flowers numerous, corymbose, pale-yellow. An- 

 nual : 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. NASTU'RTIUM. CRESS. 



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 



g'and at the base internally ; anthers somewhat heart-shaped, 

 ermen cylindrical. Style erect, short, cylindrical ; stigma 

 obtuse, notched. Pod nearly cylindrical, shortish ; its valves 

 concave, without ribs or keel. Seeds roundish, flattened, irre- 

 gularly arranged, on slender stalks. Name from nasus torsus, 

 a convulsed or distorted nose. 331. 



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

 roundish- heart-shaped, waved leaflets. Stems spreading, gene- 

 rally 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 Nasturtium. Eng. Fl. vol. iii. p. 192. 969. 



2. N. sylve'stre. Creeping Yellow-cress. Leaves pinnate, with el- 

 liptical, 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 com- 

 mon. Eng. Bot. vol. xxxiii. pi. 2324: Sisymbrium sylvestre. Eng.Fl. 

 vol. Hi. p.. 193. 970. 



3. N. terrestre. Annual Yellow-cress. Leaves pinnatifid, un- 

 equally 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. 



2 A 



