XIV 
IXTRODUCTIOX. 
by consulting a General Flora, such as De Candolle’s 
Prodromus. 
It may be well to remark here that the season of 
flowering of the plants in the descriptive pages is indi- 
cated in the usual way by the numbers of the month ; 
and that the symbols which precede these, viz. 0, $ , 
It, and T? , signify : 
0 (the Sun), that the plant is of annual duration ; because 
the earth requires a year to perforin its revolution round 
the sun. 
(Mars), a biennial plant; because that planet is two years in 
performing a similar revolution. 
1/ (Jupiter), a perennial plant or root ; because of the great 
length of time, nearly 12 years, required by that planet 
for such a revolution. 
b (Saturn), a shrub or tree ; which, living for a great number 
of years, is represented by a planet, requiring nearly 30 
years to revolve round the sun. 
Any peculiar terms employed, particularly among the 
CompositcB and Graminea , are explained at the com- 
mencement of the respective orders. Reference may also 
be made to the genera, Rosa, Rubus, and Hieracium. 
The term Rhizome has been usually applied to those 
underground stems with internodes, — whether short 
and thick as in Arum, or long, slender, and extensively 
creeping, as in Carex arenaria, — which are, in popular 
language, called roots. When, however, any difficulty is 
likely to arise, or when these require to be contrasted 
with tufted or fibrous roots in the same genus, the ex- 
pression roots has been occasionally used in the Linnaean 
sense, it being thought desirable to render this Flora 
useful to those who have not had an opportunity of 
going through a course of Philosophical Botany. For 
the same reason bulbous and tuberous roots are still 
