INTRODUCTION. 



The family GraminesB, to which every kind of grass in the botanical sense 

 belongs, is a very natural one ; that is to say, the structural characters 

 which distinguish it from other families are clearly defined. They also 

 possess a superficial resemblance in common by which they can at once 

 be identified as members of one family. 



Amongst the characters by which the various grasses may be distin- 

 guished, the one from the other, are many which are sufficiently obvious 

 to any observant person, and do not require any very special knowledge of 

 botany to be recognized. Some, for instance, such as bamboos, have thick 

 woody stems, and grow to the size of trees, whilst others are small and 

 succulent, lasting only for one year or less from germination to the ripen- 

 ing of the grain. The habit of growth is often a sufficiently distinguishing 

 character; the long creeping stems of dub (Cynodon Dactylon), for in- 

 stance ; and the tendency to climb which is the normal condition of Anthis- 

 tiria scandens, Apluda aristata, and some others. The arrangement of the 

 flowers, known technically as the inflorescence, offers many conspicuous 

 distinctions which characterize genera, or groups of species. The presence 

 or absence of hairs, bristles, or spines on or around the florets are super- 

 ficial characters and easily recognized, as also the colour of the pubescence 

 whether white, reddish, or golden. Some species emit a sweet aromatic 

 perfume ; others are highly scented during the process of drying. Some 

 kinds grow in isolated clumps, whilst others are gregarious, extending over 

 large areas in the form of pasture. Some grasses are found only near 

 water ; others appear to prefer dry sandy ground. Clay soils and calcare- 

 ous soils have each their characteristic species ; and certain kinds appear 

 to flourish better in shady places. 



The distribution of particular species over wide areas of country is large- 

 ly due to agricultural extension, for certain kinds are nearly always to 

 be found associated with cultivated crops. A knowledge of the habitat of 

 a plant is very frequently of great assistance towards its identification. 



The occurrence of certain kinds of grasses in particular localities is 

 determined to a great extent by climate ; some species, and often entire 

 genera, being restricted to the plains, whilst others cannot exist below cer- 

 tain elevations on the hills. Excessive moisture influences to a great 



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