XXVii INTRODUCTION. 
numerous as the ovaria; in spinosissima, reversa, in- 
dica, &c. they are twice; in bracteata, acicularis, ferox, 
&e. thrice; and in Lawranceana eight times as nume- 
‘rous. 
Ovaria may in some cases be usefully employed to 
distinguish species; but for that purpose it is abso- 
lutely necessary that they should be examined in the 
primordial flower. Villose have from 30 to 40, in 
which respect Rubiginose agree with them. Canine 
have from 15 to 25 except in the case of caucasea, in 
which they are from 50 to 60; and of Lawranceana, 
where they are reduced to 7. 
Styles by their exsertion and cohesion characterize 
a section, of which the species are naturally allied. 
There is one plant however (R. setigera) with this pe- 
culiarity, which differs materially in other respects, 
and having subulate stipulz stands in the division 
Banksiane. 
Fruit has been much relied upon as offering very 
evident characters; and if these were constant none 
could. be better. It however unfortunately happens 
that few parts of the plant are more subject to varia- 
tion, not only as to surface, but form and size. This 
remark is particularly applicable to tomentosa, canina, 
and rubiginosa, in which every diversity of form, &c. 
may be found. Yet there are some species in which 
it. appears to be much less polymorphous ; but whether 
from our having less knowledge of them, or from the 
absence of the predisposition to vary for which ca- 
nina and its neighbours are so famous, I do not pre- 
tend to be able to judge. Cinnamomew may be consi- 
dered to offer examples of the greatest uniformity, and 
Canine and Villose of the greatest diversity of fruit. 
