302 COMPOSITAE 



more Common. Aldermaston. Burghfield. Mortimer. Buckle- 

 bury. Newbury Wash. XJfton. Enborne, &c. 

 5. Loddon. Early Heath, Jo/insow. Bulmarsh. Bagshot Common, 

 J. Smith, Herb. Brit. Mus. Boggy ground in Windsor Park, 

 Goiobed, 1805. Ascot, WVkin. Near Caesar's Camp. Wellington 

 College. Ambarrow. Long Moor. Sandhurst. Crowthorn. 

 Wokingham. Sunninghill Bog. Whitemoor Bog, near Brack- 

 nell. Eisely. Below Finchampstead. Near Blackwater. 

 The annual plant has sub-entire leaves and a single flower-head, 

 but the biennial or perennial has often cut leaves and two or three 

 heads or flowers, and is the sub-var. polycephalus. The difference of the 

 two forms has led to the reporting of one of them as C. heteroiyhyllus, 

 which is a plant of Northern Britain not found in the Midlands. 



A hybrid with C. palustris was noticed at Long Moor — C. peatensis x 

 PALUSTRis [^ Cnicus Forsteri, Sm.). 



('. pratensis occurs in all the bordering counties. 



C. acaulis, Willd. Prod. Fl. Berol. 260 (1787). Dwarf Thistle, Stemless 



TJiistle. 

 f'ardwis acaulis, Linn. Sp. PI. 1199. C. acaulis septentrionalium, Park. 



969. Cirsiuw acaide, All. Fl. Ped. i. 153 (1785). [Web. ex] Wigg. 



Prim. Fl. Holsat. 59. C. acaulos, Scop. I.e. 131. 

 Top. Bot. 244. Syme, E. B. v. 16, t. 692. Nyman, 407. Fl. Oxf. 173. 

 Native. Pascual. Chalk downs, commons, dry heaths, open hilly 



pastures and roadsides on calcareous soil. Locally abundant, 



especially on the grassy chalk downs or dry calcareous pastures. 



It is absent from large areas on the Clays and Bagshot Sands. P. 



June-October. 

 First record. Park Place, Mr. S. Rudgs, Herb. Brit. Mus. 1800. Carduus 



acaulis, Dwarf thistle, Dr. Noehden and Mr. Bicheno on Ilsley 



and other downs, Mavor's Agr, Berks, 1809. 

 Var. CAULESCENs (Pers. Syn. ii. 389, as a var. of Carduus^, Syme, E. B. 

 t. 692, bis, is not unfrequent. I have seen it at Frilford, Besilsleigh. 

 Letcombe, Lambourn, and in an extreme state by the railway near 

 Streatley, on Stubbing's Heath and Pinkney's Green, &c. None of 

 these caulescent forms suggested hybridity. 

 C. acaulis occurs in all the bordering counties. 



C. arvensis, Bernh. Syst. Verz. Erf. 156 (1800). Cmnmon Thistle, Way 

 ThisUe. 

 Serratula arvensis, Linn. Sp. PI. 820 (1753). Carduus arvensis, Robs. 

 Brit. Fl. 163, Curt. Fl. Lond. vi. t. 57. Carduus vulgatissimus 

 tiarum, Ger. Em. 1173. Cirsium arvense, Scop. I.e. 126 (1772). 



Top. Bot. 243. Syme, E. B. v. 17, t. 693. Nyman, 410. Fl. Oxf. 174. 



