CALLITRICHE 223 



Top. Bot. 169. Syme, E. B. viii. 120, 1. 1273. Nyman, 250. Fl. Oxf. 121. 

 Native, Lacustral. Streams, ponds, &c. Local. P. May-Augxist. 

 First record. C. Autumnalis, prope Oxoniam, Sir Josex)li Banks, in Herb. 

 Brit. Mils. 1768. 



1. Isis. Buscot. Buckland. 



2. Ock. Marcham. 



4. Kennet. Burghfield. Near Shaw, Hampstead Marshall. 



5. lioddon. Sandhurst. Virginia Water. 



Var. PEDUNCULATA (DC, Fl. Fr. iv. 415, as a species). Syme, E. B. 

 viii. 121, t. 1274. C. autumnalis, Hook, in E. B. Suppl. t. 2606, not of 

 Linn. This form grows on muddy places, in woods, and by pond- 

 sides, but it is not unlikely that states of C. stagnalis, &c., may be confused 

 with it. I have notes of its occurrence in Bagley Wood, FL Oxf., at 

 Silchester, Ufton, Greenham Common, Ambarrow, Early, Windsor 

 Park, Swinley, &c. 



C. intermedia occurs in all the bordering counties. 



C. stagnalis, Scop. Fl. Carn. ed. 2, ii. 251 (1772), Water Sianvort. 

 Top. Bot. 169. Syme, E. B. viii. 120, t. 1272. Nyman, 250. Fl. Oxf. 121. 

 Native. Inundatal. Ditches, ponds, slow streams, "svet places. 



Common and generally distributed. P. April-August. 

 First recorded as C. plafycarpa by Mr. H. C. Watson in B?'itt. Contr. 1871, 

 and as C. stagnalis by the author in Rep. of Bot. Rec. Clnh, 1881. 



Var. PLATYCARPA (Kuetz. in Linnaea, vii. (1832) 174, as a species), 

 has the lobes of the fruit nearly parallel and is the commoner form ; 

 in C. stagnalis the lobes are divergent as in Baxter's figure 392. 



C. stagnalis is a very variable plant. The leaves are usually obovato, 

 but when growing on mud they become much narrower until they 

 resemble those of C. intermedia {hamidata^, from which the larger fruit 

 distinguishes it. The fruit is occasionally slightly stalked. The 

 rosettes are never quite so distinctly regular as in C. obtiisangula. The 

 plant is very frequently barren. 



C. stagnalis is too common and widely distributed to need special 

 localities being given. It occurs in all the bordering counties. 



C. polymorplia, Lonnroth, Obs. Crit. PI. Suec. 19 (1854). Nyman, 250. 

 Native. Lacustral. Shallow pools. Very local and rare, but perhaps 



overlooked. P. June- August. 

 First found by the author in Berkshire in 1895. 



4. Kennet. Near Theale. I believe my specimens are rightly 

 named from descriptions, but I have not compared them witii 

 typical plants. 

 C. polymorplia is recorded for Surrey only of the bordering counties. 



C. obtusangTila, Le Gall, Fl. Morbihan, 203 (1852). 

 Top. Bot. 169. Fl. Oxf. 121. Nyman, 250. 



