60 LETTER IV. 



these little leaves is hence a mark of the Cruciferous 

 tribe. Observe, I pray you, how very useful it is to 

 be aware of this. Imagine yourself cast away upon 

 a desert island ; and there, surrounded by plants of 

 unknown forms and tempting looks, none of which you 

 dare use from fear of their proving poisonous. Among 

 them however you remark a good many of the same 

 kind, one of which is just beginning to bear its tufts 

 of flowers : the blossoms are too young to be examined, 

 but old enough to shew you that they grow without 

 bracts ; the leaves you would easily see were those of 

 Exogenous plants, and you would immediately know 

 that this species at least would be not only harmless, 

 but the very best kind of vegetable for you to consume; 

 a salad which might be eaten with the utmost con- 

 fidence. 



But it is not thus alone that Cruciferous plants may 

 be recognised. The structure of their flowers is of a 

 very peculiar kind. The calyx is formed of four little 

 leaves or sepals ; within which are four very small 

 white petals, arranged in the manner which I have 

 already stated gave rise to the appellation of Cross- 

 bearers {jig. 1.). Within the petals are six stamens 

 {Jig. 2.), of which two are a very little shorter and 

 more spreading than the other four. To this cha- 

 racter no parallel is to be found in any other than 

 Cruciferous plants, and consequently it is a second 

 essential character, by which they are to be known. 



The pistil is an oval green body, shaped something 

 like a wedge, on the summit of which is a little 

 cushion of a stigma seated on an exceedingly short 



