42 HORTUS GRAMINEUS WOBURNENSIS. 



pointed or awned, joints of the culm smooth, sheaths of the leaves 

 hairy, leaves smooth and succulent, contain most mucilage and 

 extractive. 



7th, Grasses with flowers in a panicle, florets thinly scattered, 

 pointed, or furnished with long awns, culms lofty, with few joints, 

 leaves flat and rough, contain a greater proportion of saline matter 

 and bitter extractive. 



8th, Grasses with strong creeping roots, culms few, leaves flat 

 and rough, flower in a spike, contain a greater proportion t)f bitter 

 extract, with mucilage. 



The above general description of the figure and properties of 

 grasses, considers every part of the plant, and is therefore termed 

 the natural character of grasses. 



The simplicity of form which runs through the whole structure 

 of this order of plants, can admit of but few very obvious varia- 

 tions to distinguish the different species from each other ; which 

 indeed appears in the foregoing enumeration of terms that repre- 

 sent them. 



The parts of fructification, the flower, and the seed, are the least 

 liable to vary from any change of soil or cultivation ; and Botanists 

 have chosen them on that account, to fix their generic distinctions : 

 or, when the flowers and seeds of any number of grasses agree in 

 one or two particular points, and differ therein from all the rest, 

 such are termed a genus or family. The difference in the manner 

 of inflorescence, and the form of clothing of the culm, leaves, and 

 roots, afford the specific characters, or separate the genus into spe- 

 cies : when the difference between two grasses amounts to little 

 else than one or two of these last-mentioned points, or when such 

 distinctions are either lost or found by raising the plant from seed, 

 it is then considered a variety.* These characters of genera, 

 species, and varieties, being founded on a few parts only, and 

 those frequently not very obvious, have been termed artificial 

 characters of distinction. The memory, by these means, is re- 

 lieved from a multiplicity of minute distinctions, which would not 

 be the case were all the parts of the plant included in the essential 

 specific description or character. 



* When a variety retains those marks of distinction after being raised from seed, 

 it is called a permanent variety ; when it loses those distinctions, it is then styled 

 an accidental variety. See Smith's Grammar of Botany, and Smith's Introduction 

 to Systematical and Physiological Botany. 



