QNOPORDUM 303 



Native. Agrestal. Cornfields, roadsides, waste places. Abundant 

 and ubiquitous. One of our commonest species. P. June-Sept. 

 First record. Sonning, Mr. S. Rudge, in Herb. Brit. Mus. 1800. Serra- 

 tula arvensis, Mavor's Agr. Berks, 1809. 



C. arvense occurs under several modifications. White-flowered forms 

 are not unfrequent, as at Hinksey, Eaton, Hastings, Compton Beau- 

 champ, Sparsholt, Inkpen, Sulhampstead, Barkham, Hawthorn Hill, 

 and Clewer. 



Var. Tunis = Cirsium arvense, var. mife, Koch, Syn. Fl. Germ. 400 (1837), 

 as the name denotes, is a much less prickly form than the type ; it is 

 found in more shady situations and in richer soil, and appears to 

 merge gradually into the typical form. I have seen it near Ascot, 

 Wantage. Windsor, Waltham, Tidmarsh, Theale, Kintbury, Basildon. 

 Appleford, Marcham, Charney Basset, Lyford, Longworth, Dean- 

 court, Ferry Hinksey, &c. 



Var. HORRiDus (Koch, 1. c. under Cirsium) is the very spinous form 

 which is frequent in dry places ; it is common on the Chalk downs, 

 &c., as Blewburton, Lambourn, Catmore, Hungerford, Inkpen, Ilsley, 

 Compton, Sonning, Bisham, Stubbing's Heath, Warfield, the drier parts 

 of Windsor Park, &c. This form again appears to merge gradually into 

 the intermediate form. 



Var. SETOsus (M. Bieb. Fl, Taur. Caucas. iii. 560, as a species of 

 Cirsium), Syme, E. B. v. 18, t. 694. See Bess. Prim. Fl. Galic. ii. 172=- 

 var. integrifolius (Koch, 1. c. under Cirsium), is a third and more 

 distinct form, which is probably a sub-species, and is rather a 

 colonist than a native plant. It is of rare occurrence, and is usually 

 found on rubbish heaps or waste ground. It was first noticed by the 

 Rev. C. W. Penny in 1874 in the brickyards near Wellington College. 

 Mr. F. T. Richards found it by the river near Oxford on the Berkshire 

 side in 1888 ; I have seen it by the railway at Didcot and Beading, 

 and on waste ground near Windsor, Grandpont, and on Abingdon 

 Racecourse. It remains constant in cultivation. 



C. arvensis occurs abundantly in all the bordering counties. 



ONOPORDUM, Linn. Gen. n. 834 (Vaili. Act. Par. 17 18, f. 37). 

 Onopordon Acanthium, Linn. Sp. PI. 827 (1753). Cotton Thistle. 



Acanthium vulgare, Park. 979. A. album, Ger. Em. 1149. 

 Top. Bot. 245. Syme, E. B. v. 2, t. 680. Nyman, 402. Fl. Oxf. 171. 

 Native or denizen. Viatical. Roadsides and hedge-banks and waste 



places. Local and rather rare. B. July-September. 

 First record. West Hagbourn, Mr. J. Lousley, in Russell's Cat. 1839. 



1. Isis. Between Besilsleigh and Appleton. 



2. Ock. In the roadside near the turnpike gate, West Hagboui-n, 



Lousley, 1. c. Dry Sandford, Boswell. Tubney, Walker. Radley. 



