Crops and Weeds of Arable Land 79 



The plant is a typical mediocre grass-form, tillering in field-cultivation lo 3-5 

 culms, with a maximum of 60-100 when single plants are grown isolated under 

 special conditions, as on a manure-heap. The inflorescences are compound 

 condensed spicate systems; the spikelets, with several flowers, setting 2-4 seeds 

 each. In the original state the spikelets bore long awns in the manner of 

 Barley (Bearded Wheat), and the main rachis broke up into separate segments 

 for dispersal by the wind (Emmer). Vestigial awns commonly occur on 

 ' Beardless Wheats ', and the grain lies loose in the pales and is readily threshed 

 out ' naked '. The seed is sown in early autumn (September), to take advantage 

 of warm rains, 1 on land ploughed generally following Beans or Clover, in drills 

 6 in. apart. The seedlings come up in 2-3 weeks; and by the end of 

 November the fields are covered with a green mantle, 6 in. high. Little growth 

 takes place over the winter, until March ; the crop increasing in density during 

 April and May. The tillering shoots send up culms increasing by telescopic 

 extension of the internodes from below, to 3 ft. in mid-June. The plants flower 

 at Midsummer (4-5 ft.) and the crop is matured early in August. 2 



As a short-season grass of a warm Mediterranean climate, 3 the wheat is still 

 autumn-sown ; but in a northern summer the vegetating period is extended by 

 2 months, and the plant is so far an exotic beyond its normal dispersal range, 

 now maintained wholly artificially by man, and not running wild. Seedlings in 

 unoccupied ground, as waste-heaps, may grow more or less successfully a second 

 season, but rarely come up a third. As in the case of the American Zea Mais, 

 the mechanism of auto-dispersal has been completely eliminated in cultivation. 



The periodicity involves an autumn germinating season, and a summer 

 growth continued a month longer than the hay-crop of indigenous grasses. 

 Weeds germinate and grow up with the crop in a close association which cannot 

 be weeded readily except by hand and in early stages. 



Western civilization is based on the production of food-grains of which 

 Wheat is predominant as alone giving good ' bread ', together with Barley as an 

 inferior corn, no longer employed for bread, but essential for brewing beer. 

 The condition of English Agriculture has followed the evolution of methods 

 for dealing with such cereals, and any consideration of the weed-accidentia of 

 the crop requires some historical presentation of the special problems of its 

 cultivation. 



Fallow. The ancient barbaric custom of growing corn to the exhaustion 

 of the soil and then moving on, implies a more or less nomadic habit and 

 abundance of free land. More settled civilizations of the Eastern Mediterranean, 

 with clearer ideas of property ownership, introduced the practice of fallowing, 

 with the object of giving the land a rest (cf. the fth Sabbatical year in 

 Palestine). In Greek and Roman cultivation a general practice (Virgil) let the 

 land lie fallow, and grow a crop in alternate years. This solved the problem 

 of Fungus-diseases (Rust, Puccinia; Smut, Tilletia; Claviceps, etc.) which 

 inevitably follow a pure successional crop grown on a large scale ; as the 

 perennating fungus-spores normally germinate in the succeeding spring, but 

 do not last another year. The herbaceous weeds were probably taken as 

 granted. The common weeds of corn-land to-day are but the same as those of 

 the fields of Carthage and N. Africa which supplied the corn of the later 

 Roman Empire. 



As a matter of fact, the exhaustion of the land was due to the great growth 

 of weeds in successive years, and the land becoming ' foul ' required to be 

 cleaned. In a field left derelict the alien weeds of cultivation would, in the 

 course of time, go down before the indigenous flora, more particularly the 



1 Orr (1916), p. 197. Cf. older custom of beginning at the end of July. In the early season of 

 1921 fields were steam-ploughed for wheat after beans, in the first week of August. 



' In the dry summer of 1921, wheat was harvested before the end of July. 



* In Palestine wheat was sown at the onset of the rainy season at the end of October, and grew 

 throughout the mild wet winter, to be harvested in Apiil or early May, as a 6-month crop. Barley, 

 sown in February, less water-demanding, with surface-roots, as a short-season cereal, is also harvested 

 in May, in 3 months. In Alaska, with ' midnight sun ', wheat is harvested in 90 days from sowing. 



