INTRODUCTION. 



xvii 



corolla husks ; but it is very minute, tender, and finely transparent. The terms employed t 

 describe the corolla, likewise apply to this. It is not found in the genus Nardus, Erioplonm 

 Alopeciirus, or Sesleria. i 9 



h 



VI. 



Varieties of the Seed. 



The discriminating characters of the seeds of grasses are confessedly minute ; but as the form 

 of the seed is never known to vary, except by disease, the marks of distinction it offers are of 

 the most unerrmg kind. In most grasses the seed is covered, or enclosed, by the husk' which 

 was formerly the blossom, ( corolla J; in other species the seed is naked, or so loosely attached 

 to the husk, as to separate from it in the process of cleanino-. 



If the seeds of every species of grass were naked, their^liminutive size would hardly afford 

 any obvious marks of distinction ; but the coat, or seed-vessel, (peHcarp.u^n), gives variety to 

 the form oi those seeds, which are otherwise very mucli alike. 



The discriminating characters of the seed being thus minute, and resting almost always on 

 various shades of dissimilarity assumed by three or four principal figures, as, round, oval 

 oblong, and acuminate or pointed, it is therefore easy to conceive, that such distinctions ar^ 

 often readily perceived by the eye on comparison, but with difficulty conveyed by mere descrip- 

 tion ; meed it may be said, that a few hours' practice in comparing the different kinds of seed 

 with each other, is worth a volume of description, for practical purposes. With this view, and 

 also to shew where the principal characters of distinction take their rise, the following speci- 

 mens, illustrative of the different genera, are selected ^ 



th 



e \ 





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I 



'^Vj 



I 

 f- 



