392 Plant as an Index of Smoke Pollution 



of Leeds and the Yorkshire Council for Agricultural Education. The 

 tubs were then placed, two at each station, in four different parts of 

 Leeds. At only one station, that furthest north, did they flower the 

 first year. In the second year more than eight feet of growth was made 

 at Adel three miles to the north, while in the industrial area of Hunslet 

 one plant only survived, a wizened, flowerless specimen, nine inches 

 high. 



Plants which have to "lay up a store for another year" tell their 

 own tale of smoke pollution. Heavily handicapped in their growth by 

 the effects of these atmospheric impurities they have little chance of 

 laying up reserves. This is noticed both in the case of the bulbous and 

 seed-bearing plants. Radishes will grow in Hunslet, but they will run 

 to leaf and will not form bulbs. Tulips, narcissi, daffodils, scillas and 

 hyacinths can be grown there and they will flower one year, but if a 

 second year's bloom is desired, the bulbs must be replaced. Wheat, oats 

 and barley can be grown in Hunslet, and you will get plants, but the 

 grain, as can be seen from Fig. 1, PI. XXI Y, will not be worth the 

 harvesting. You may grow lettuces and cabbages in Hunslet, but you 

 must not expect them to heart. 



A casual glance at the hedgerows will give some guide as to the 

 extent of smoke pollution in any particular area, for the hawthorn is 

 one of the smoke-sensitive plants and one of the first to go under. 



Notice the flora of the lawns and fields of any particular district. 

 In a smoke-infested area, the leguminous plants, the clovers and vetches 

 will be conspicuous mainly by their absence. The finer grasses, particularly 

 the fescues, will be missing. Coarse growing grasses like bent, couch and 

 Yorkshire fog will be in the ascendant, and acid loving plants like dock, 

 sorrel and plantain will abound. If a lawn is required in the industrial 

 area of Leeds it must be sown down each year. 



In the Hunslet Parish churchyard, surrounded on all sides by huge 

 chimneys belching out smoke, even bent and the hardy Poa annua have 

 been killed, and the only sign of vegetation is to be found in a few 

 straggling blades of twitch still struggling for existence. The garden of 

 a large residential house left stranded close to the church is a pitiable 

 sight. Its only flower is the iris which still blooms freely, its only shrub 

 or tree is the elder; its only fruit or vegetable is the rhubarb, and its 

 only grass is twitch. 



Though, apparently the elder will grow anywhere, no matter how 

 great the pollution from coal smoke, it can still give some indication as 

 to the amount of that pollution. Though it will grow in the industrial 



