128 LETTER VIII. 



scarcely to be visible ; the flowers growing in com- 

 pact clusters ; and the stamens not only very nu- 

 merous, but so long and slender and delicate as to 

 resemble silken threads tipped with very little an- 

 thers. If you can imagine such a structure you will 

 have a sufficiently correct idea of the Mimosa divi- 

 sion, the beauty of which, on account of the multitude 

 of flowers they bear, and the gay colours in which 

 they are invested, is of so peculiar an appearance, 

 that one of them, a nearly hardy tree (Acacia Juli- 

 brissin), is actually called by the Persians, in whose 

 country it grows, the Gul ehruschwiy or Rose of Silk. 

 Here belong the curious Sensitive plants (Mimosa), 

 whose many parted leaves shrink from the touch of 

 the very wind that blows upon them, W'hich close up 

 and appear to go to sleep at night, and which seem 

 as if struck with sudden death if they receive any 

 rude shock ; of these plants the balls of flowers are 

 peach-coloured. To the genus Acacia^ of W'hich 

 great numbers are found in New Holland, where 

 they are called Wattle Trees, also belong the spiny 

 gum trees of Arabia and Senegal ; the greater part of 

 the species have yellow flowers, and many of them 

 broad dilated leaf-stalks, in room of the many-parted 

 leaves which they bear when young. 



The diff'erences of these three divisions of the Pea 

 tribe may be expressed thus : — 



Flowers papilionaceous . . Papilionaceous Plants. 



^ Stamens few — Cassias. 

 Flowers not papilionaceous j 



' Stamens numerous — Mimosas. 



