02 



TAXONOMY. 



the fruit is improperly called naked, because it presents 

 Caryopses with a simple covering, and frequently even Nuts. 

 In the fifteenth class, the idea of a silicula causes some diffi- 

 culties in the first Order, because in many genera we observe 

 true nuts without the power of bursting. 



Similar exceptions may be made to the orders of the nine- 

 teenth class. No doubt this arrangement promises much at first, 

 because in the first order of the nineteenth class, Syngenesia, 

 Polygamia aqualis, the flowers have all equally good seed, 

 and are all hermaphrodites. In the second order, S. P. su- 

 perflua, the flowers on the margin are only female, those in 

 the centre hermaphrodite, but they are all equally fruitful. 

 In the third order, *S'. P. frustranea, the flowers on the mar- 

 gin are neutral, or the pistillum is abortive, but the flowers in 

 the centre are hermaphrodite, and alone bear perfect seed, 

 In the fourth order, S. P. necessaria, the relation is exactly 

 reversed : the central flowers, which are commonly male, are 

 abortive, and only those on the circumference, which are for 

 the most part female, bear perfect seeds. Lastly, in the fifth 

 order, S. P. segregata, every flowret has also its separate 

 calyx, although they all stand upon a common receptacle. 



To this division it may be objected, that very often the 

 Jrustranea, in the same genus, coincides with the aqualis ; 

 for in Bidens and Centaurea, for example, a neutral ray of- 

 ten makes its appearance, and often fails. The same thing 

 happens in some genera of the superflua, where Anthemis, 

 Jnacyclus, and Pyrethrum, sometimes lose the ray. But 

 these objections affect every other division of this class in an 

 equal degree ; for the Cynarese pass into the Radiatae, and 

 •vice versa. In like manner we might notice, respecting the 

 segregata, that what has been called their peculiar calyx, is 

 often nothing else but chafiy leaves, as we also see them in 

 many genera of the remaining orders. 



138. 



These, and similar defects, induced the founder of this 

 system, during his later years, to think of some improvements 

 on it. 



