NUMBER OF PLANTS KNOWN. 165 



collected nearly four thousand different species, 

 most of them new. 



The whole number of plants, at present known, 

 may be estimated at thirty-three thousand ; with- 

 out including those peculiar to New Holland. 

 Those belonging to the class Cryptogamia, already 

 published by various authors, exceed six thousand. 



But we must come back to the class Didynamia ; 

 and we shall now examine the common Ground- 

 Ivy, which is a good example of it. [PLATE 16.] 



There are two orders in this class, the first called 

 Gymnosper'mia, in which the seeds are naked; 

 the second, Angiosper'mia, having the seeds covered. 

 Pull out one of the blossoms, and tell me to which 

 of these orders the Ground-Ivy belongs. 



EDWARD. 



I suppose it must be the first; for I see four little 

 seeds in the bottom of the cup, without any cover- 

 ing. But what were the two little white crosses 

 that I saw in the blossom? 



MOTHER. 



They were the anthers; but you must not be too 

 sure of their number, until you have opened the 

 blossom ; you will then find that what you took for 

 a cross, is in reality composed of two parts, so shaped 



that when they meet, 1) C <^C they look like 



a little cross. This is what constitutes the prin- 

 M 3 



