224 The Flora of f/ic ('tnitbrtfff/c DtxtriH 



climbs among the lower branches of the bushes. On tin- 

 ridges Fctfurft nriiui is dominant, L^mlinlnH ///x///V//x and 

 Hieradum Pilosella abundant, and some grasses such as A /-;// 

 pratemis and Koelerid, crixtnta common in places. A count 

 of plants on a square yard of rather bare soil gave 



125 plants of Festuca ovina. 

 40 Leontodon hispidus. 

 8 ,, Hieradum P/A/.WA/. 

 3 ,, ,, Gentiana campestrt*. 

 2 Poly gala calcarea. 

 2 seedling grasses Arena pratensi*. 



The ground had been recently disturbed and consisted of 

 small angular pieces of chalk, favouring a strongly xerophytic 

 flora. On a soil less recently disturbed some of the Legumi- 

 nosae appear, notably a very hoary form of Medicago htftn- 

 lina and Trifolium ochroleucon. 



The eastern division unlike the rest of the Cambridge 

 district is largely open country, man has hardly influenced it ; 

 here and there plough lands may be seen, and round Mild en- 

 hall a certain amount of tree planting has been attempted, 

 but as a whole the soil is too poor to repay any labour spent 

 upon it. Rabbits abound and these affect the flora to a very 

 considerable extent (see p. 227). 



The strata north and south of the river Lark differ slightly, 

 and with them the flora. To the north over a great extent 

 of country, from Mildenhall to Lakenheath and Thetford, two 

 species of plants are dominant, Carex arenari and /'//'//.< 

 aquiliim. These do not occupy the same ground ; there may 

 be patches one hundred yards square of either, and it is not 

 at all obvious which is driving out the other or, if they are in 

 a state of equilibrium, what cause determines the distribution. 

 Possibly the nearness of the chalky subsoil to the surface, by 

 affecting the drainage, may determine this, but until more 

 work is done on this question it is impossible to speak 

 definitely. It has therefore appeared good to class the 



