4i6 ]\'oodniffv-Pciicock : Flonil Co))if)ctitioii und (ydes. 



above j^rouiid, in a soil so tliin and dry thai the plants die off 

 before the end of May,- they are free from competition. 



There is a clear distinction between broken-g"round and road- 

 hedg^e-side species. One, speaking^ j^enerally, is the refuge of 

 annuals, which can stand little crowding, the other, of biennials 

 and perennials capable of enduring much more ; naturally peren- 

 nials cannot flourish in a soil that is annually cultivated, unless, 

 like Agropyron rcpciis or .Igrosfis stolonifera, they are specially 

 furnished for the purpose. There are, however, many curious 

 and to me as yet inexplicable exceptions. Sisymbrium officinale, 

 for instance, is far more often found in biennial localities than in 

 annual areas. It may be on account of its short flowering time, 

 but more likely on account of its mode of growth, i.e., the time 

 between the seed germination, and seed shedding. 



There is another glaring misinterpretation of facts, and of 

 published book records, lying at the root of our accepted estimate 

 of the value of species as native or alien. It is one that has 

 practically been most fruitful of errors in attempts at ' making ' 

 pasture and meadow-land. F'verything' is changing and fluctu- 

 ating in the world of plant life, but on clear and definite lines. 

 There is a perfectly regular sequence and cycle from broken 

 ground to pasture. If you care to follow the course further, to 

 forest, swamp and peat bog, in Ireland at present, and formerly 

 in our greater or smaller fens in Lincolnshire, when Eastern 

 England had a much moister climate than now. The com- 

 bination of species in the flora this season is not exactly, only 

 approximately, the same on any spot, as that of last year. The 

 cycle can be studied at one point only at a g-iven spot, and it 

 must ever be remembered that it is only a section that can be 

 under review at any one place or time. It is, therefore, the 

 greatest folly to expect the species or combinations of any other 

 portion of the cycle to be there, 



A piece of tilth falling perfectly naturally to pasture — 

 * tumbled down ' g^rass it is locally called —exhibits according to 

 its age, the nature of the soil, rainfall, and stocking it i.as 

 received, many \ aried and perfectly definite changes. These 

 gradually fit the ground, to be the home for the time being of a 

 long succession of species in temporary combinations. The 

 earliest occupiers of the ground are soon thrust aside, and each 

 combination in turn that follows them, steadily but more slowly, 

 gives place to some other selection, as root soil and nitrogen 

 accumulate, and the turf g^rows closer and competition more 

 keen. What is true of a pasture growing in quality, is equally 



.Naturalist, 



