X. 
PART IV. HOW TO USE THE KEY. 
Supposing the student to have gathered a specimen quite 
unknown to him, he will turn first to the General Key on page 1, 
and determine under which of the Sections he is to look for his 
plant. If, to take a simple example, he has a spray of A/der, he 
will at once see that it should be looked for under section A., 
“Trees and Shrubs.” ‘Turning to page 3, he finds two alternatives 
joined by a bracket, ‘“‘ Leaves made up of separate leaflets,” and 
(at the bottom of the page) ‘‘ Leaves not of separate leaflets.” As 
his leaves have several leaflets, he goes on under the first heading, 
and has to decide between “‘ Leaves opposite,’ and ‘‘ Leaves not 
opposite.”’ Proceeding under ‘ Leaves opposite,’ he recognises 
successively that the leaves of his plant are not entire (having 
numerous teeth), and that the lower pair of leaflets are stalked 
and the flowers white, and that his plant is therefore Sambucus 
nigra, the common Evder. 
He will soon become familiar with the different Sections, 
and will find that, in the few cases where he is in any doubt under 
which of them he should look, his plant may be found under 
either of the doubtful alternatives. 
He must remember, however, always to take the Sections in 
order. The common AHfoneysuckle, for instance, will not be 
found among the irregular flowers, under section F., because it 
had been already included, as a climbing plant, under Section A., 
and similarly the Water-/ily will not be found under Section J., 
because already dealt with as an aquatic plant under Section C. 
In the example given above the student was led, in one of 
the Sections of the General Key, to the name he required, that is 
to say the name of the particular kind, or “‘ species,” of plant which 
he had gathered. Such names always consist of two words, the 
first being the name of the “genus,” and the second the “specific” 
name proper, which distinguishes the particular species from all 
the rest grouped together under the same genus. 
In many cases the search under the General Key will only 
result in a name consisting of a single word. If this is printed 
with only one capital letter, it is the name of a genus, and the 
student must turn to where it comes, in alphabetical order, among 
the generic Keys commencing on page 63, in order to find out 
the specific name. Thus supposing, in the former example, the 
General Key had only given him the name Sambucus, he 
would turn to page 119, where the generic Key would bring him 
to the specific name nigra, the complete name he requires being 
therefore Sambucus nigra. If the name is printed entirely 
in capitals, it is that of one of the families or “ Natural Orders” 
