CORNFIELDS 



235 



so is Creeping Speedwell, which grows usually 

 in meadows. 



Effect of Dressing, &c. A cornfield or allied 

 cultivated tract is unique amongst botanical 

 habitats in the fact that the soil is enriched 

 each year with some form of manure or 

 dressing. Normally no other type of vegeta- 

 tion receives the same type of dressing. 

 Humus accumulates in a wood or hedge, and 

 as a thin layer in meadows, whilst peat and 

 humus (thick) play a great part in moors, bogs, 

 and heaths. But though these are organic 

 soil renewers, they do not resemble in effect 

 the artificial dressings in the cornfield. 



The direct result of such manuring is to 

 cause the plants (weeds included) in a cornfield 

 to present generally a robust, well-matured 

 appearance. They are usually luxuriant and 

 in marked contrast to similar or allied species 

 growing elsewhere. The peat or humus- 

 loving plants are not represented as a whole 

 in the cornfield flora, and most of them are 

 fond of clay, sand, or lime, and these soils are 

 improved by the addition of manure in one 

 form or another. At the same time there are 

 some plants that dislike dressing, and will not 

 grow under such conditions. The discovery 

 of the requirements of plants in this respect 

 will be an object for inquiry here also. 



Effect of the Soil. The conditions required 

 for the effective growth of a cereal crop are 

 light but fertile soils, which are dry and warm. 

 The soils that furnish these conditions are 

 mainly sandy loams, clayey loams, and cal- 

 careous soils. Rocky, too sandy, or siliceous 

 soils do not give a deep or rich soil. Heavy 

 clays are also unsuitable. Marls are, however, 

 well suited for cereals. 



These conditions are not always found in 

 the soil itself without cultivation or improve- 

 ment, hence the plants that would naturally 

 come up in a cornfield are not always to be 

 found on the soil, but are replaced by others, 

 that may be introduced from elsewhere. But 

 in some cases the weeds that are common to 

 the district are able to adapt themselves to the 

 altered conditions, and where a sandy soil is 

 improved by the addition of lime, plants that 

 prefer the former may still linger, and where 

 the latter is the principal natural soil the 

 addition of loam may not affect the lime-loving 

 plants. 



As a rule, the cornfield plants are those that 

 grow naturally upon a sandy soil or a sandy 

 loam. A few such, as the Hemp Nettle, are 

 lovers of clay as well. A fair proportion are 

 characteristic of limestone or chalk areas, such 

 as Larkspur, Candytuft, Flax, Venus's Look- 

 ing Glass, Small Snapdragon. Some are 

 able to subsist on either, as the Red Poppy, 



Shepherd's Needle, Fool's Parsley, Lamb's 

 Lettuce, Cornflower, and Blue Sherardia. 



Dry-soil Types. The preponderance of the 

 sand plants in cornfields owing to the con- 

 ditions required by cereals, such as lightness 

 and dryness of soils, is a well-marked feature, 

 which is explained by the processes to which a 

 cornfield is subjected in fitting it for cultivation. 



The transition from the damp conditions of 

 the woodland to those of a meadow is less 

 great than from those of a meadow to those of 

 a cornfield. It is true that the cutting down 

 of trees has a great effect upon a district in 

 making it as a rule much drier, and a meadow 

 also has usually been drained before it is used 

 for pasturage, &c. 



In a cornfield, however, these conditions 

 have been already fulfilled before a further 

 stage, that of cultivation and better drainage, 

 with yearly ploughing, is attained. These 

 last factors tend to make the soil very much 

 drier, and owing to this a cornfield is the 

 extreme stage towards dry-soil conditions, 

 which in a meadow are not nearly so well 

 marked. The shielding of the lowest zone of 

 plants amid the corn in mid and later summer 

 does not prevent the free access of the sun to 

 the soil and the rapid evaporation of the 

 surface moisture. 



Consequently, as would be expected from 

 the natural predilection of the great majority 

 of the plants for sandy soils, the plants in a 

 cornfield are mainly xerophilous or dry-soil 

 types. There are, in fact, few if any of them, 

 except perhaps Corn Sow Thistle and Mouse- 

 tail, that will grow in a moist habitat. White 

 Campion is intermediate in this respect. 



Methods of Survey. The mode of examina- 

 tion of a cornfield flora differs very little from 

 that of a meadow or pasture, except that the 

 cereal itself supplies the dominant plant. 



Proceeding to examine the cultivated area 

 first of all, it may be pointed out that Grasses 

 have been artificially eliminated, and therefore 

 the best means of studying the flora is to take 

 each tier or zone by itself, and to estimate the 

 dominance of the several plants that make up 

 each zone. In some fields Creeping Thistle 

 will be dominant in the zone corresponding to 

 the tree zone, with Corn Sow Thistle propor- 

 tionally next so. 



In the intermediate zone, if the Creeping 

 Thistle does not occupy this, we may have 

 Corn Marigold. Charlock and Corn Butter- 

 cup may come next. In the ground flora the 

 dominant plant may be Ivy-leaved Speedwell, 

 early in the year, and Scarlet Pimpernel later. 



Mousetail grows sporadically in the furrows 

 rather than in large societies. The vegetation 

 of the borders, especially the cornfield plants, 



