ON THE CHALK 299 



Violdcece)—m.a,y be found in some limestone and chalk districts, 

 and also on some diy soils removed from calcareous rocks. It has 

 no runners like those of other species, and its cordate leaves are 

 very hairy, on petioles covered ^^dth spreading hairs. The flowers 

 are scentless, pale violet or white, \\dtli bracts below the middle of 

 the peduncle ; and the spur of the corolla is long, blunt, flattened, 

 and hooked. 



Two species of Flax (order Linacece) are to be found on chalky 

 soils. One — the Perennial Flax {Linum perenne) — grows in hilly 

 districts, but is not at all common. It is a slender plant, with 

 numerous wiry stems from one to two feet high ; and sessile, linear, 

 acute leaves. The petals are of a beautiful sky-blue colour, but 

 so hghtly attached that it is difiicult to secure a perfect specimen. 

 The other species — the Xarrow-leaved Flax {L. angustifoliwn) — is 

 moderately common on calcareous hills of the South and West of 

 England. It is very similar to the last, and grows to about the same 

 height, but its many stems are more irregularly branched, and the 

 alternate leaves are Hnear-lanceolate. The corolla is of a Hghter 

 lilac-blue colour. L. perenne blooms dming June and July, and 

 the narrow-leaved species from June to September. The latter is 

 shown on Plate VIII. 



Quite a number of species of leguminous plants (order Legumin- 

 osce), may, as a rule, be met wdth on dry soils, but only two common 

 ones may be described as particularly partial to chalk and lime- 

 stone localities. These are the Tufted Horse-shoe Vetch {Hippo- 

 crepis comosa) and the Sainfoin or Ck)ck's-head [Onohrychis saliva). 

 The former, represented on Plate VIII, is a low, smooth, prostrate 

 plant, six to eighteen inches long, \%dth yellow flowers that bloom 

 from May to August. This plant is sometimes confused with the 

 Bird's-foot Trefoil, which it rather closely resembles in general 

 appearance, but it may be readily distinguished by the pinnate 

 leaves and the pecuHar form of the pods. The latter are flattened, 

 and break up, when ripe, into from three to six one-seeded, horse- 

 shoe-shaped segments — a feature which has given rise to the popular 

 name. 



The Sainfoin is often cultivated in the South-East of England 

 as fodder for cattle, but may frequently be found growing wild. 

 It is a very pretty, erect plant, from one to two feet high, with 

 dense racemes of rosy-red flowers beautifully striped with a darker 

 tint. The stem is stout and downy, and the pinnate leaves have 

 membranous stipules and numerous oblong leaflets which terminate 



