4 
Mir. Ha worth's new Arrangement 
that of Ray, Petiver, and Plukenet; extended the history of succu- 
lent plants to a far greater degree than it had before arrived at. 
On the continent also, particularly in Holland, the subject had 
rapidly advanced ; and multitudes of species had been collected 
and cherished, and many of them figured and described by Mun- 
tingius, in his Aloidarium; by Breynius, Burman, and Boerhaave; 
by the two Commelines, father and son; and by Volckamer, Tilli, 
Herman, and others. 
Yet, notwithstanding the force of such bright examples as these, 
the whole subject, for more than half a century, has not by any 
means kept pace with the other departments of botany, but has 
been almost entirely neglected ; no work on succulent plants, ex- 
clusively, having appeared during all that time, nor any other 
publication which has much advanced our knowledge of them, 
except, indeed, the Hortus Kewensis of the late Mr. Aiton, and 
my own Observations on the Genus Mesembryanthemum ; in which, 
after regretting my inability to figure the numerous species of 
that genus, I recollect expressing an anxious wish, that some 
other person more able than myself would take up the business, 
and do so. 
At length I have the happiness to say, that this wish has been 
more than complied with in France, by the authors of a perio- 
dical work now publishing in Paris under the title of Plantes 
Grasses, who appear to have undertaken the figuring not only of 
this my favourite genus, but of all other succulent genera. An 
impartial account of some errors attending those figures and their 
accompanying descriptions I have already had the honour of lay- 
ing before the Linnean Society. 
I shall conclude this preface with observing, that the Aloes, 
like all other intricate or extensive families of plants, require sec- 
tions and subdivisions to render the investigation of their compo- 
nent 
