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LECTURE IV. 
Examination of Flowers belonging to different Ctajjes* 
The Clajfes 19, 20, 21, and 22, explained. 
As a in cans to imprefs the knowledge 
which has been acquired upon the minds of 
my pupils, and in order to render their ft'udies 
more amufing, I recommend to them to at- 
tempt to refer fome plants of fimple tonftrue- 
tion to their clafTes and orders. The young 
botanift is frequently difcouraged in his early 
endeavours of this kind by the flowers on 
which he fixes for his experiments ; the whole 
tribe of graffes mould be avoided,- as they re-* 
quire a 1 peculiar method of ftudy, an-d confider- 
able proficiency in the knowledge of botany, 
to render them eafy of accefs. The ftate of 
the flower, when examined, is alfo an impor- 
tant circumftance ; the beft time to examine 
the number of ftamens is immediately before 
the corol expands ; after the anthers are ma-* 
turc it is difficult, in many flowers, to diftin- 
guifli their number. The hippuris vulgaris, 
mare's 
