BOTANY 



as the field ragwort or mountain fleawort {Senecio campestris) and the cat's- 

 foot {Antemiaria dioica) require. The process appears to be complete so 

 far as exterminating the former is concerned, while the latter, with the 

 spotted cat's-ear [Hypochceris maculata), only linger in a solitary locality. 

 It must also be borne in mind that with the growth of the richer herb- 

 age of the grasses I have named, there is a greater attraction held out for 

 sheep and cattle to come to these once arid places. They assist the pro- 

 cess by trampling down to a dead uniformity both the vegetation and 

 the soil, while with their advent a new factor is introduced, namely the 

 nitrates which result from the ammonia excreted by them, which foster 

 the growth of the Poa and Dactylis, but are inimical to the older and 

 rarer species. Nor must the influence of the atmosphere be forgotten. 

 With the streaming rain and gentle dew a continual dissolving away and 

 washing down of the original rock is taking place, and brought by the 

 driving wind, particles of soil of a different character from the bed-rock 

 are deposited. Before such agents as these the reprehensible maraudings 

 of the too greedy botanical collector sink comparatively to nothing. 

 Change of this kind is slowly taking place everywhere in Britain, but 

 much more rapidly with us, since our rocks are all soluble, and the pro- 

 cess is necessarily much more rapid than it is with the igneous rocks, 

 which weather but slowly, and especially when the other factors of high 

 cultivation, and a more densely populated area also are to be found. 



A similar process goes on in our small heathlands, and the introduc- 

 tion or the increase of rabbits largely assists in it, since they nibble off 

 very closely all the aboriginal vegetation, so that the annuals such as the 

 bird's-foot trefoil {Ornithopus), the buck's-horn plantain {Plantago coro- 

 nopus), the small trefoil {"Trifolium fiUforme) — the latter not yet recorded 

 for Northants — have a very bad time, and only such hardy species as the 

 ragwort {Senecio Jacobcea) appear to be able to hold their own ; while 

 their rapid movements tend to distribute the nettles, the seeds of which 

 get scattered from their furry coats. The stone quarries near Weedon, 

 at Cosgrove, and heathy roadsides and heathlands of Holdenby, H addon, 

 etc., are now much poorer than they were even in my recollection, and 

 the mountain fern [Lastrea Oreopteris or Dryopteris montana) has been era- 

 dicated. The broom {Sarothamnus scoparius) is now much scarcer, and 

 its interesting parasite, the broom-rape {Orobanche Rapum-genistce) is now 

 almost extinct. 



The replacement of stone buildings with those made of brick has 

 caused a diminution in the number of mural plants. We read in Ray's 

 Itineraries that he found on the walls of Northampton several interesting 

 plants, and we know that the drawing of the wall pennywort or navel- 

 wort {Cotyledon Umbilicus) in the first edition of English Botany was made 

 by Sowerby from plants gathered on the walls of Peterborough Cathe- 

 dral, but now few plants of any kind are found on the less congenial 

 brick walls of Northampton, and the better state of repair in which the 

 walls of Peterborough Cathedral are kept yield little space for the Coty- 

 ledon, which it is to be feared has been quite exterminated there. Doubt- 



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