HORTUS GRAMINEUS WOBURNENSIS. 43 



Though most of the genera are considered as merely artificial, 

 yet there are several which have their nutritive matters of a de- 

 scription peculiar to themselves. Sir Humphrey Davy informs 

 us, that the nutritive matters from the diflerent species of fescue, 

 in general, afford more bitter extractive matter than those from the 

 different species of poa, and that the seed crop of the Phleum 

 pratense n.fforded more sugar than any of the poa or festuca species. 



M. St. Hilaire, in his Exposition of the Natural Families of 

 Plants,* arranges grasses according to the number of the styles, 

 the stamina, and the number of florets contained in each calyx. 

 Accordingly he divides grasses into ten sections. 

 Sect. I. Contains such grasses as have 2 styles, and 1, or 2 

 stamina. 

 II. Grasses which have 2 styles, 3 stamina, and the calyx 

 1 -flowered. 



III. Grasses furnished with 2 styles, 3 stamina, calyx con 



taining two flowers, one of which consists of stamina 

 only. 



IV. Grasses which have 2 styles, 3 stamina, calyx 2 or 



3-flowered, the flowers of different sexes. 

 V. Consists of grasses which have 2 styles, 3 stamina, calyx 1 



or 2-flowered, all the flowers bisexual. 

 VI. Grasses furnished with 2 styles, 3 stamina, calyx many- 

 flowered, flowers glomerated. 

 VII. Grasses with 2 styles, 3 stamina, calyx many-flowered, 

 flowers in a spike, or situated on the axils of the stalk ; 

 terminating floret male, or barren. 

 VIII. Contains the grasses which have 2 styles, 3 stamina, and 

 calyx many-flowered. 

 IX. Grasses with 2 styles, and 6 or more stamina. 

 X. Grasses which have their style unique, summit simple, 

 and 3 stamina. 

 From the great simplicity of the above natural system, its merits 

 are obvious ; yet, like all others that have been framed, it is in 

 some degree imperfect, as there are several species which possess 

 characters that entitle them to a place in more than one section. 

 For practical purposes, therefore, an arrangement which partakes 



* Exposition des Families Naturelles, et de la Germination des Plantes, par 

 Jaume St. Hilaire. Paris, 180o. — Consult also Smith's English Flora, vol. i. 

 p.^39 et xeqq., for the most scientific and useful arrangement of British Grasses. 



