T.0 BOTANY. 239 
amples, where the Difference confifts prin- 
cipally in thofe Parts of the Plant. Thus, 
Aculei are remarkable in Rubus. 
Spines in Prunus. 
Braétea in Fumaria, Dracocephalon, and 
the Indian Species of Hedyfarum; to which 
mutt be added the Coma, which is a bufhy 
Head, compofed of Bracfee that are of a 
large Size, and terminate the Stem in Corcna 
imperialis, Lavandula, and Salvia. 
Glandules furnifh the effential Mark in 
Padus, Urena,. Mimofa, Cafia, and many 
other Genera, which it would be impoffible 
to diftinguith without being acquainted with 
this Part. They are found on the Serra- 
tures at the Ba/e of the Leaves in Helzocar- 
pus, Salix, and Amygdalus; on the Back of 
the Leavesin Padus, Urena, and Pafffora; 
and onthe Acu/ei in Baubinia aculeata, where 
by the Apex of the Acu/ed a Liquor is fe- 
creted. The Amygdalus is diftinguifhed from 
Perfica only by the Glandules of the Serra= 
" fures ; nor could the Species of Urena be ever 
fixed without examining the Glandules of 
the Leaves. The Convolvulus with a tuber- 
culate Calyx, is fo variable in the Shape of 
its Leaves, that it feems divifible into many 
Species, yet is kept together by the G/an- 
dules: And there is a Species of Monarda, 
diftin~ 
