Mr Macvicar on the Seed of the Stipa Pennata. 345 



accidents; may be propagated both by sporules produced in pro- 

 per seedvessels, by germs and otherwise. 



But besides this beautiful law, the action of which may be 

 distinctly recognised, preserving the species of organised beings 

 in existence, notwithstanding the perpetual destruction which 

 they wage against each other ; we are able to observe the traces 

 of another no less beautiful, that, in proportion as a species is 

 useful in the economy of nature, so are the developement and ef- 

 ficiency of the organs and functions that effect its diffusion. 



This might be inferred a priori, from what we know of the 

 attributes of the Creator, and the analogy of his works. This^ 

 however, is a mode of reasoning not admitted in Natural History, 

 in which a law must only be framed, as a generalised statement 

 of a number of observed phenomena, tending to a common pur- 

 pose. But that such a law exists we observe many traces of evi- 

 dence. Thus there is no tribe of plants more eminently useful 

 in the economy of nature than the grasses, the foliage and seeds 

 of which supply the first necessaries of life, not only to man but 

 to a multitude of the inferior animals. And, perhaps, in no tribe 

 equally highly organised, do we observe the same tenacity of 

 life, or the same economy and care in the reproductive organs, 

 to avoid the introduction of parts that might be easily injured, 

 and so prevent a successful fructification. 



In the grasses, the delicate coloured flower that gives so much 

 beauty to most other tribes, is replaced by concave husks, which 

 are not only most hardy, but so situated that the weather can 

 scarcely penetrate to injure the essential organs within. Besides 

 this, the peculiar structure of the embryo, which admits of a 

 number of stems from one seed, might be mentioned, the copious 

 albumen, &c. But I proceed to describe, and a few words will 

 sufiice, the beautiful structure of the awn exhibited in a species 

 of this family, which effects the introduction of the seed into 

 the soil so wonderfully, that I cannot satisfy myself with ad- 

 miration. 



The Stipa pennata is a most elegant species of grass, which, 

 though not a native of Scotland, thrives luxuriantly in the open 

 border. Its seed is closely invested by the glumaceous perianth, 

 which consists of two husks, a larger and a smaller, the former 

 of which overlaps the edges of the latter, and almost entirely 



