PRACTICAL WORK 



185 



pondingly. Hedgerows are particularly interesting in wilder parts 

 of the country where they are not trimmed too frequently, as 

 many of the natural wild plants of the district take refuge there. 



If nothing but a rubbish heap is to be had, observations on 

 Plant Associations can still be made. Here the type of vegetation 

 is usually distinctly xerophytic. The interesting problem is to 

 find out how the plants on the rubbish heap got there. If near a 

 brewery yard, the explanation is easy. In the barley imported 

 from abroad, many seeds of foreign plants are brought over and 

 effect a lodgment on any heap of rubbish. A corn store with 

 wheat from America may account 

 for several of the plants found 

 on the mounds, covered, it may 

 be, with Nettles, Docks, Ragwort, 

 Thistles. One of the most common 

 plants on city rubbish heaps is the 

 Annual Mercury, with dark green 

 leaves and opposite branches. Very 

 small staminate flowers, with yellow 

 anthers, are borne by slender upright 

 flowering branches. The pistillate 

 flowers are not on the same plant as 

 the staminate ; the branches bearing 

 these are much shorter than in the 

 case of the staminate ones. This 

 city plant is not unlike the Dog's 

 Mercury found in woods and shady FIG. 5 5 .-Ann U ai 



, J J annua). Young fruits on left side. 



hedge banks. Another very common 



weed on waste places is the Hedge Mustard, a forlorn-looking plant. 

 The lower leaves are much cut up, and have a large terminal 

 lobe ; the upper ones are narrow. The flowers are yellow and 

 very small. The pods are pressed closely to the stem. Another 

 Crucifer, with small white flowers and flattened seed-vessels, that 

 frequents rubbish heaps, is the Hoary Cress (Lepidium draba). 



The same rubbish heap should be constantly visited, in order 

 to find out what new specimens locate themselves there from 

 time to time. Another situation that is very fertile in unexpected 

 plants is a railway embankment. Plants are not much disturbed 



