ON WALLS, ROCKS AND STONY PLACES 327 



order Scrophulariacece) which bloom from July to September. The 

 plant varies from one to two feet in height, is tufted and leafy at 

 the base, and has erect stems which bear racemes of large flowers. 

 The leaves are very narrow and entire ; and the flowers, which are 

 usually white, pink or crimson, are shortly stalked in the axils of 

 the small upper leaves. The calyx is deeply divided into broad 

 lobes very much shorter than the corolla ; and the latter consists 

 of a broad tube and two lips, the whole being over an inch in length. 

 The mouth of the flower is closed by a projecting ' palate,' but is 

 easily opened by pressing the flower at the sides between finger 

 and thumb. There are four stamens on the corolla, two longer 

 than the others ; and the fruit is an unsymmetrical capsule that 

 opens when ripe by a few holes near the top. 



The Ivy-leaved Toadflax or INIother of Thousands {Linaria 

 Cymhalaria), of the same order, is a pretty little traiUng plant very 

 commonly seen on old walls in many parts of Britain, particularly 

 in the South-West. It will grow luxuriantly in places where there 

 is no soil other than that afforded by the crumbling mortar, and 

 will often establish itself even on new walls so compactly built 

 that it is difficult to see how the plant can find the necessary moisture 

 or how its roots can penetrate the hard material to which it is 

 attached. Its slender stems vary from a few inches to two feet 

 in length, often rooting at the nodes ; and its little leaves are smooth, 

 with three or five lobes, and generally of a purplish colour on the 

 under side. The Uttle flowers, which bloom from May to September, 

 are of a pale blue or lilac colour. The lipped corolla is very similar 

 to that of the last species, with a yellowish palate closing the mouth, 

 but it has a short spur at the base. 



The one remaining flower of this chapter is the Wall Pellitory 

 {Parietaria officinalis), which belongs to the Nettle family ( Urticacece). 

 It is a somewhat bushy plant, varying from six inches to two feet 

 in height, bearing axillary clusters of small, sessile, green flowers 

 from June to September, and is common on walls and stony banks, 

 more especially in the South of England. Most of the flowers are 

 usually imperfect, and the clusters are surrounded by a whorl 

 of a few divided bracts. The males are few in number, each con- 

 sisting of a hairy perianth, and four stamens which are jointed 

 and very elastic, springing suddenly and shedding their pollen 

 when touched ; the females have a tubular, hairy perianth of four 

 lobes, and a single tufted stigma. 



