LILIACEOUS PLANTS. 



65 



86. Comparing this flower with that of Dog's-tooth 

 Violet, we find the two to exhibit a striking resemb- 

 lance in structure. But in one respect the plants are 

 strikingly unlike : the leaves of the Trillium are net- 

 veined (Fig. 87), as in the Exogens. From this circum- 

 stance we learn that we cannot altogether rely on the 

 veining of the leaves as a constant characteristic of 

 plants whose parts are not in fives. 



TRILLIUM. 



87. The two plants just examined are types of the 

 natural Order Liliacece. The distinguishing characters 

 are a,s follows : 



1. The parts of the flower are almost invariably in sets 



of three, the perianth being of two such sets, and 

 also the stamens. The flowers are therefore sym- 

 metrical ; they are also regular. 



2. The stamens are opposite the divisions of the perianth. 

 8. The ovary is nearly alivays S-celled^ and is superior. 



