GEOGRAPHY OF PLANTS. 499 



NOTES ON THE WHEAT PLANT, 'ITS RANGE, ETC. 



Altliougli the plants which the earth produces spontaneously appear to be 

 confined in range within certain districts, and few of them wouki survive a wide 

 change of circumstances, creative Providence has, nevertheless, endowed many 

 of those most essential to man with a greater flexibility of structure, so that 

 the limits of their production may be extended by culture beyond what have, 

 in many instances, been assigned to them by nature. The grasses that jneld 

 grains are especially favored in this respect, their culture having been much 

 extended through the knowledge and industry of man. The Cerealia also 

 affords remarkable examples of very numerous varieties derived from one 

 species. In Ceylon alone there are one hundred and sixty varieties of rice ; 

 of 'Panicum, or millet, very many kinds ; and of Tritimm, or wheat, we have a 

 few well-defined species, which have been increased until, by different modes of 

 cultivation, and the influence of soils and climate, more than two hundred 

 varieties have been produced. From the well-defined species accepted by 

 botanists, and which may be described in general teiTus as the hard wheats^ 

 the soft wheats, and the Polish wheats, all the innumerable varieties known to 

 agriculturists have descended. The hard wheats are the product of warm cli- 

 mates, such as Ital}', Sicily, and Barbary. The soft wheats are grown in the 

 northern parts of Europe, as in England, Belgium, Denmark, and Sweden. 

 The Polish wheats grow in the country from which they derive their name, and 

 are also hard Avheats. The hard wheats contain much more gluten than the 

 other varieties. This valuable ingredient is a tough, viscid substance, very 

 nutritious, and which, as it abounds in nitrogen, readily promotes fiu-mentation 

 in the dough, and is essential to good light bread. The quantity of nitrogen 

 varies with the soil and climate from five per cent, in some soft wheats to 

 thirty per cent, in the hardest and most transparent. It is the higher propor- 

 tion of gluten that exists in Italian wheats that fits tliem for use in the prepa- 

 ration of macaroni and the rich pastes that form so large a portion of the food of 

 the people of that land. The softer v.-heats contain a larger proportion of starch. 

 The latter are usually grown in England, and require to be Avell dried and 

 hardened before they can be readily ground into flour. 



We have said that many of these varieties of wheat have resulted from influ- 

 ences derived from the soil. Some soils are remarkable, far and wide, for 

 producing good seed, and it is equally well known that this seed degenerates in 

 other soils, so that the original is resorted to for fresh supplies of seed. This is 

 so well known in England that the produce of a certain parish in Cambridge- 

 shire is sold for seed at a price considerably above the average. It is not, 

 however, the experience of all that the finest wheat makes the best seed, but in 

 the choice of seed the nature of the soil upon which it is to be sown must be 

 considered as well as that upon which it grew. 



It has been asserted that all the various noted seed-wheats, when analyzed 

 by the chemist, are found to contain the different elements of which they are 

 composed in nearly the same proportion, especially the starch and gluten. For 

 bread, that which contains the most gluten is preferred ; but to produce a per- 

 fect vegetation there should be no excess of this substance, and no deficiency, 

 and the seed should have arrived at perfect maturity. Moreover, it has also 

 been stated, and with great apparent probability of its truth, that if we wish to 

 grow any peculiar sort of wheat, and find by our preparation of the soil or its 

 original composition that we produce a wheat in which the gluten and starch 

 are in different proportions ft-om that of the original seed, we may conclude that 

 this is owing to more or less nitrogenous matter in the soil — that is, more animal 

 manure — or proportionally more vegetable humus; and by increasing the one 

 or the other, we may bring our wheat to have all the properties of the original 

 seed. By selecting seed from those ears which appeared superior to the others 



