XVI PREFACE. 



some districts, through the successful practice and recommend- 

 ation of Mr. Coke, of Norfolk. 



Thus, out of 215 distinct species of grass, which are capable 

 of being cultivated in this climate, (many of which differ in value 

 from each other, as much as wheat does from pilcorn), two only 

 have been cultivated separately to any extent. The cause of so 

 much delay in the advancement of improvement in this important 

 branch of the Farmer's art, may appear extraordinary ; but there 

 have been serious difficulties in the way. 



" Grass," says Professor Martyn, " vulgarly forms one single 

 idea; and a husbandman, when he is looking over his enclosure, 

 does not dream that there are upwards of three hundred species 

 of grass, of which thirty or forty may be at present under his 

 eye. They have scarcely had a name, besides the general one, 

 till within these twenty years ; and the few particular names that 

 have been given them are far from having obtained general use : 

 so that we may fairly assert, that the knowledge of this most 

 common and useful tribe of plants is yet in its infancy." * 

 Botanists have ascertained that there are 133 distinct species and 

 varieties of grass, natives of Great Britain : every one of these 

 species differs, in a less or greater degree, from all others, in the 

 qualities which alone render them of value to the Farmer : com- 

 paratively speaking, some grasses are of no value to him, whilst 

 others constitute the foundation of his riches, as they are the 

 staff of life to the most valuable domestic animals. Now, though 

 the numerous species and varieties of grasses differ so widely 

 from each other in value, yet the similarity which pervades their 

 whole structure is too great to afford any certain marks of dis- 

 tinction, without having recourse to particular rules, made from 

 a consideration of those parts of their structure which are not 

 subject to vary from culture or change of situation. The bota- 

 nical or discriminating characters, of which these rules consist, 

 are often minute, and sometimes perplexing, even to professed 

 Botanists : to those, therefore, who have made Botany no part of 

 * Martyu's Letters on the Elements of Botany. Letter XIIL 



