44, REPORT—187 4. 
racters, abridged from the last ‘Genera Plantarum’ or other best sources, 
selecting chiefly those which are most essential and contrasted, but including 
also the most striking or the most general amongst the adaptive ones, and a 
general indication of geographical range, with careful reference to the works 
where more details are to be found. 
Where the orders or genera are large, a synopsis or conspectus of the 
principal divisions and subdivisions would be useful. ‘ 
To each species should be given :— 
(1) The name. 
(2) The diagnosis, specific character, or abridged description, which are 
but different names for the same thing, and which it appears to me would 
be always more satisfactory in the nominative than in the ablative case. 
After the example of Linnzus, and based upon the doctrine of the fixity of 
species, it has been almost universally the custom to distinguish the specific 
diagnosis and description, the former to contain the absolutely distinctive 
characters (any deviation from which would exclude a plant from the spe- 
cies), the latter to aid the student in identifying a plant by the enumeration 
of characters which, though general, might vary in the same species, or 
which it may possess in common with other species. In order to mark the 
more strongly this difference, the diagnosis, when in Latin, has been given 
in the form of the ablative absolute, the description in the ordinary nomina- 
tive form. There is, however, nothing really absolute in nature. There is 
no class of characters which may not occasionally admit of exceptions; and 
although care should be taken to select the most important and constant 
ones, yet, in some instances, those which are generally discarded as too 
variable for a diagnosis, such as dimensions, colour, &c., may yet be most 
useful, or even essential, for the distinction of species or even of genera. 
These diagnoses, moreover, to be useful should be short. We cannot now 
restrict them to the twelve-word law of Linneus, but a twelve-line ablative 
diagnosis is an absolute nuisance. 
(3) Reference to the source whence the diagnosis is taken, to the work 
where a further description, tle synonymy, and history of the species are to 
be found, and to any plates where it may be satisfactorily represented ; and 
all further synonymy should be avoided, except where it may be necessary 
to refer to descriptions, names, or modifications published since the one 
specially abstracted from. 
(4) The habitat of the species. 
(5) Occasional notes on affinities or other points in the history of the 
species should be very sparingly indulged in, and only when they may assist 
essentially in the provisional determination and elucidation of a plant. All 
discussions on doubtful points and all details should be reserved for mono- 
graphs or separate papers, where alone they can really tend to the advance- 
ment of the science. 
Each volume of the ‘Synopsis’ would of course be accompanied by a full 
index of genera, species, and such synonyms as it may have been found 
necessary to give. 
The whole work would be so indispensable to botanists of all nations, that, 
like the ‘Genera Plantarum,’ it should be entirely in botanical Latin, which, 
moreover, from the number of conventional expressions to which a technical : 
meaning has been assigned, is specially suited for short diagnoses. 
No new species should be first published in this ‘Synopsis.’ Nothing has 
tended more to produce confusion in systematic botany than the publication 
of real or supposed new species, with short diagnoses, unattended by any full 
