148 VASCULAR PLANTS. 



ORDER XXXVm. CENTROSPERMiE. 



Perigonium 0. Ovules basilar. 



Family CV. Naidaceae. 



Flowers diclinous. Ovary 1; 1-locular, 1-ov- 

 ulate; fruit a nutlet. 



1. Lilaea, hbk. 



Flowers monoecious : 6 spicate, 1-bracteate, 

 monandrous , sometimes mingled with ? flow- 

 ers, which are partly spicate and 1-bracteate; 

 partly solitary, axillary and ebracteate. Styles 

 of the upper flowers short, of lower, elongate; 

 stigmas capitate. 



0. aquatic; leaves radical, terete sheathing 

 at base. 



2. Zoster a, L- 



Flowers monoecious. Spathe elongated into 

 a lamina. Spadix flattened, naked dorsally, 

 covered by alternate stamens and ovaries ar- 

 ranged in 2 rows. Anther 1-locular, sessile. 

 Ovary rostrate; style persistent. 



%. stems rooting, submerged. 



Family CVT. Lemnaceae. 



Aquatic plants without axis. Flowers en- 

 closed in a thin, membranaceous spathe. Sta- 

 mens 1 — 2; anthers 2-locular. Ovary sessile, 



