LETTER XV. 



THE BORAGE TRIBE — THE NIGHTSHADE TRIBE 



THE PRIMROSE TRIBE. 



(Plate XV.) 



I HOPE that you will have found the distinguishing 

 characters of all the Monopetalous orders we have 

 examined up to this time sufficiently clear and defi- 

 nite to he understood and rememhered ; and that as I 

 have been proceeding, you have been analysing their 

 distinctions after the plan of which some instances 

 have been already given you. For I am convinced 

 by long experience that this is the only sure way of 

 fixing such matters in the memory. As it is my in- 

 tention, after we shall have gone through the whole of 

 them, to analyse for you such of the Monopetalous 

 orders as I may select for illustration, it is unnecessary 

 for me to dwell as yet upon their mutual distinctions. 

 Let us, on the contrary, proceed, for the present, 

 steadily in our examination of other natural orders. 



Of all the groups into which Botanists have di- 

 vided the Vegetable Kingdom, there is none which 

 combines uniformity of general appearance with 

 similarity in structure in a greater degree than 

 those rough-leaved plants, which Linnseus used, on 



