204 J. HOPKINSON — FOEMATION AND 



attached to sheets of paper, will be contained in our herbarium, 

 which would best be placed in drawers or cupboards underneath 

 the cases. As this separation is merely a matter of convenience, it 

 need not be further referred to here, except to say that exigencies 

 of space only, render it necessary to stow away specimens which are 

 pressed and dried when collected, and will lie flat in the herbarium, 

 the arrangement of which should be precisely the same as that of 

 the collection in the show-cases. It may frequently happen that 

 parts of the same plant may have to be separated, the fruit or seed, 

 for instance, being placed in the show-case, and the rest of the 

 plant in the herbarium. 



With regard to the linear arrangement, it appears to me that 

 the most usual system adopted in our British Floras, of commenc- 

 ing with the highest group and ending with the lowest, is not a 

 desirable one. It is surely the most philosophical to begin with 

 the lowest and simplest forms of life, and to proceed onwards to 

 the higher and more complex forms, whether they are to be 

 treated of in a text-book or arranged in a museum. 



No better scheme for the classification of the plants of the whole 

 world has, I think, been devised than that proposed by Lindley in 

 his great work * The Yegetable Kingdom,' though it is not perhaps 

 so suitable for the plants of such a small area as our own county. 



All plants may be primarily divided into cryptogamous and 

 phanerogamous. Cryptogamous or flowerless plants are divided by 

 Lindley into the classes (1) Thallogens, comprising algse, fungi, 

 and lichens ; and (2) Acrogens, comprising mosses, lycopods, and 

 ferns. All these may be represented in our museum. I'hanero- 

 gamous or flowering plants Lindley divides into the five classes 

 (3) Rhizogens, in which class there are no British plants ; (4) 

 Endogens, containing grasses, orchids, lilies, etc. ; (5) Dictyogens, 

 containing yams and parids ; (6) Gymnogens, containing coniferous 

 trees, etc. ; and (7) Exogens, in which class are comprised by far 

 the greater number of our forest-trees, shrubs, and herbaceous 

 flowering plants. Exogens are divided into the sub-classes 

 Diclinous, Hypogynous, Perigynous, and Hypogynous Exogens ; 

 and these again, as well as the other classes, contain assemblages of 

 the natural orders grouped together in divisions called alliances. 



In the accompanying table (Table II, pp. 208-210), while 

 adopting the general plan of Lindley, I have made considerable 

 alterations in his scheme in accordance with the views of recent 

 writers on our British Flora. Lindley's class Dictyogens is here 

 added to Endogens, and his class Gymnogens to Exogens ; instead 

 of his arrangement of the sub-classes, that of De Candolle-' is 

 followed; the Characefe are removed from Thallogens and con- 

 sidered as forming the lowest group of Acrogens ; and I have 

 altered the sequence and arrangement, and in some instances the 

 extent, of the natural orders and alliances. 



* As given in Babington's 'Manual of British Botany,' 7tli edit., 1874. The 

 last edition (the third) of Lindley's 'Vegetable Kingdom' was published in 1853. 



