54 CRUCIFERAE 



SISYMBRIUM, Linn. Gen. PI. n. 728 (Tournefort, t. 109). 



S. Thalianum, Gay in Ann. Sc. Nat. vii. (1826) 399. Turkey pod, Mavor, 

 Arabis Thaliana, Linn. Sp. PI. 665. S. TliaUana, Hook. fil. Stud. FL 

 27 (1870). 



Top. Bot. 41. Syme, E. B. i. 163, t. 115. Nyman, 45. Fl. Oxf. 30. 

 Native. Rupestral, glareal, ericetal. Sandy fields, heaths, and walls. 



Locally abundant. A. April and May, and sometimes in 



September. 

 First record. Draba siliquosa similis planta praecox annua, nobis. Pro- 



venit in agris frumentaceis humidis passim circa Oxonium, Morison 



Hist. Ox. ii. 235, 1680. Arabis thaliana, Dr. Noehden, Mavor's Agr. 



Berks, 1809. 



1. Isis. Carswell, Miss M. Riven. Faringdon. Cumnor. Near 



Besilsleigh. 



2. Ock. ' South Hinksey, seems rare here,' Bosivell MS. Marcham, 



Walker. Denchworth, Wait. Frilford. Sunningwell. Cothill. 

 Tubney. Besilsleigh. Near Culham. 



3. Pang. Streatley, Pamplin. About Bradfield, Jenkinson. Abundant 



near Bucklebury. Aldworth. Tidmarsh. Frilsham. Withy 

 Coppice near Basildon. Hermitage. Tilehurst. Purley. 



4. Kennet. Near Newbury, Weaver. Silchester. Kintbury. Cur- 



ridge. Burghfield. Aldermaston. Mortimer. Theale. Buckle- 

 bury Common. Welford. Snelsmore Common. Beenham. 

 AVickham Heath. Padworth. Ufton. Hampstead Marshall. 

 Southcote. 



5. Loddon. Twyford, Fl. Oxf. Finchhampstead, Penmj. Hailey, 



Stanton. Windsor, Bolton King. Wargrave. Maidenhead. Hur- 

 ley. Ruscombe. Sonning. Hurst. Binfield. Bracknell. 

 Wokingham. Sunninghill. Ascot. Windsor Park. Bagshot 

 Heath. Bray. Waltham. Pinkney's Green. Cookham. 

 Although so common on the dry sandy fields of some parts of the 

 count}' it is rare or absent on the clay, so that in the Isis district it 

 would be classed as one of the less common plants. It is also scarce in 

 some portions of the Vale, and is practically absent from the upper 

 grassy chalk downs. 



The plant forms a connecting link with the genus Arabis, and occurs 

 in pll the bordering counties. 



S. officinale, Scop. Fl. Carn. ed. 2, ii. 26 (1772). Hedge Mustard. 



S. officinarnm Erysimum, Crantz, Stirp. Austr. i. 54 (1769'. Erysimum 



vidgare, C. B. Pin. 100. E. officinale, Linn. Sp. PI. 660. 

 Top. Bot. 45. Syme, E. B. i. 143, t. 96. Nyman, 44. Fl. Oxf. 30. 

 Native. Viatical and agrestal. Roadsides, waste places, and arable 



ground. Common and generally distributed. P. April-September. 



