Grey Rock and Thyme 177 



the limestone, is the wild clematis, or old man's 

 beard, as it is called in some limestone regions. 

 As the leaves begin to fall in September, the down 

 of its ripening seed-plumes whitens on hedge and 

 tree ; and when the splendours of late October 

 blaze among the beechwoods and thickets of the 

 hills, they are illumined by its cascades and 

 streamers of hoary grey. 



Just as the soil governs the flora native to each 

 district, so the character of the plant-life has a 

 strong influence on the local butterflies and moths. 

 Though the perfect insect may drain the nectar 

 from many different blossoms, in its hungrier cater- 

 pillar period it is often strictly dependent on a 

 small group of plants, or even on a single species. 

 The variety of plants and grasses in the herbage 

 of the limestone hills has thus attracted for ages 

 a distinctive and richer insect life than is found 

 on many other soils. The difference is to be noticed 

 most strikingly when the same tract of country 

 offers an easy comparison between the limestone 

 and some heavy clay. In many clay districts the 

 monotony of plant-life is remarkable. The land- 

 scape may be no less verdant than that of other 

 soils, and the fields and hedgerows hardly less bright 

 with flowers. But a small group of species have 

 the task of clothing the entire face of the soil, and 

 recur with a poverty-stricken monotony. Yet 

 within less than a mile, perhaps, the skirts of the 

 limestone hills are rich with thyme and marjoram, 

 centaury and yellowwort and St. John's wort, 

 among characteristic flowers, as well as their own 

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