4.60 Retrospective Criticism. 
and the other leaf of the sheet of paper applied to its opposite one, having . 
the loose pieces of paper and plants between them. After which one or 
two of the books should be placed on the outside of the paper, and remain 
there until as many other plants as are intended to be preserved have been 
prepared in like manner. A layer of sand, an inch deep, should then be 
put into the box, and afterwards one of the plants, with the books placed 
upon it, which last should be removed after a sufficient quantity of sand is 
put upon the paper, to prevent the plant from varying its form.* All the 
other plants may then be put into the box in the same manner, with a 
layer of sand about an inch thick between each, when the sand should be 
gently pressed down by the foot, and the degree of pressure, in some mea- 
sure, regulated by the kind of plants in the box. If they are stiff and firm, 
as the holly or furze, much pressure is required. If tender and succulent, a 
less degree is better, for fear of extravasating the juices, which would 
injure the colour of the plant ; but particular care should be taken to make 
a sufficient degree of pressure upon the expanded blossoms of plants, that 
they may not shrivel in drying. The box should then be caretully placed 
before a fire, with one side a little raised, or occasionally flat, as may be 
most convenient, alternately changing the sides of the box to the fire, 
twice or thrice a day; or, when convenient, it may be put into an oven in 
a gentle heat. Jn two or three days the plants will be perfectly dry. The 
sand should then be taken out with a common plate, and put into a spare 
box, and the plants carefully taken out also, and removed to a sheet of 
writing paper.” (Whateley, in Withering’s Botany, vol.i. p. 28.) 
The Practice of Travellers, in disseminating Exotics among our Indigenous 
Plants. — Sir, I beg to call your attention to the following extract from 
the valuable and highly interesting new edition of the Arrangement of British 
Plants, in which a practice, worthy surely of severer reprobation, is thus 
courteously condemned :— Additions and corrections, p. 442. vol. iv. 
“ Antirrhinum Cymbalaria. In reference to the note, add: Since writing 
the above, we observe an acknowledgment, on the part of a certain enthu- 
siastic naturalist (see Mag. Nat. Hist., Vol. I. p.400.), of his having sown 
the plant in question on the rock near Barmouth; a practice from which 
other similar errors have originated, and concerning which, as tending to 
create confusion in science, among those especially who would wish to see 
the stations of our native plants defined with accuracy, there can be but 
one opinion. E.” — Your insertion of this notice may be the means of 
deterring other travellers from conduct so reprehensible, and will moreover 
oblige — A Constant Subscriber. Bristol, May 29. 1830. [Is not the beauti- 
fying of our wild scenery a thousand times more valuable than this exclu- 
sive devotion to a single science.?] — Cond. 
Disseminating Exotics, and mistaking them for British Plants. — An 
impression was formerly too prevalent, that the Flora of the British 
islands had been so fully investigated, that no new discoveries could be 
made; and this misconception has been strengthened by the deservedly 
unsuccessful attempts to introduce mere varieties as species, through the 
medium of the later editions of Withering’s Botanical Arrangement. But a 
new and more auspicious era has now commenced; and while the taste for 
natural science is daily augmented and diffused by the zeal of its professors 
in the various universities of the three kingdoms, the recent additions to 
our British plants in Dr. Hooker’s newly published Fora, as well as those 
which had but a short time previously appeared, for the first time, in the 
Englhsh Flora of Sir J. E. Smith, are sufficient to show that our own 
country may still possess‘ 
“ * Those of the genus Potamogéton, and others of the same kind, ought 
to be put into the sand without loss of time, and well pressed, otherwise 
they are apt to dry too fast, and shrivel.” 
