138 AN INTRODUCTION 
GC Hea: RB. TEER: 
By what Parts of Fructifcation the Genus 
may with the mofi Certainty be determined. 
‘HE more conftant any Part of the 
Frudtification is found through the’ 
feveral Species of any Genus, the more it 
may be relied on with Certainty as a cha- 
racteriflic Mark for that Genus: Thus in 
Hypecoum the NeGarium is conftant, but not 
the Siiqua; the Convallerta is conftant in 
its /potted Berry, but not in its Corolla; the 
Lobelia in its Corolla, but not in its Fruit; 
the Caffa in its Corolla, but not in its Si/z- 
gua; and the Verbena in its Cafyx and C- 
rolla, but not in its Stamina and Seeds. 
In fome Genera one Part of the Fruétifi- 
cation is found to be the moft conftant, and 
in others another; ut there is no Part that 
is not liable fometimes to a Variation ¢ 
Thus we find the Pericarpium variable in 
Impatiens, Campanula, Primula, Papaver, 
Ciftus, Fumaria, and Arbutus ; the Calyx in 
Nymphea, and Cornus; the Corolla in Vac- 
cinium, Convailaria, Andromeda, Gentiana, 
and Linum; and the Seeds in Ranunculus, 
and Alifma. 
If 
