192 LETTER XVI. 



into four lobes ; its fruit consists of four black grains, 

 which are the divisions of the ovary in a hardened 

 state, and in fact it is so very like the fruit of a plant 

 of the Borage tribe, that I am quite sure when you 

 look at its monopetalous corolla, you will believe that 

 it belono^s to that natural order. 



But pursue your examination of it a little further, 

 and see whether its other characters are also in ac- 

 cordance with those of the Borage tribe. Its leaves 

 for example— are they covered with stiff hairs ? no — 

 are they placed alternately on the stem ? no — have 

 they the insipid taste, &c. of the Borages ? no — are 

 the flowers arranged in a coiled or gyrate inflores- 

 cence ? is the corolla regular ? are there flve stamens ? 

 to all these questions the answer still is no, no, no. 

 The Black Horehound does not belong to the Bo- 

 rage tribe. 



Look then rather more exactly into the structure 

 of the flowers ; for there can now be no doubt that it 

 is a part of some natural order you have not yet ex- 

 amined. Its calyx (Plate XVI. 1.^^. 1.) is a tube 

 with five sharp-pointed teeth («.), and is consequently 

 formed of five sepals. The corolla is hairy and tubu- 

 lar at the base {fig. 1.), and divided at the top into 

 two unequal parts called lips ; of these lips the upper 

 is narrow and concave (Z*.), the lower is flat, and di- 

 vided into three lobes (c), of which that in the middle 

 is much larger than the two side ones ; this corolla 

 is therefore very irregular. To see the stamens dis- 

 tinctly, the best plan is to slit open the corolla {fig. 

 2.); you will then find that there are four of them, 



