DESCRIPTIONS OF GENERA. 



flONOCOTYLEDONE/E (Stem Endogenous). 



Order 1. TYPHACEAE. 



1. Ti/pka. 1-seeded. closely aggregated on an elongated axis, very 

 small, on long stalks which bear numerous hair-like bristles. Marsh herb. 



Order 2. SPARGANIACEAE. 



2. Sparganium. Nut-like, 1 or 2 celled, 1 or 2 seeded, obpyramidal, 



closely aggregated in globular heads with interspersed scales. Marsh 



herbs. 



Order 3. NAIAD ACEAE. 



3. Potamogeton. Drupaceous, 4 or less to each flower, flesh scant. 

 Aquatic herbs (entirely submersed). 



Order 4. ALISMACEAE. 



Akenes, several from 1 flower, the 3 outer perianth divisions per- 

 sistent. Marsh herbs. 



4. AUsma. Akenes in a circle, flattened. Heads numerous, pan- 

 icled. 



5. JEchinodorus. Akenes in a head, turgid, ribbed. Heads several. 



6. Lophotocarpus. Akenes in a head, flattened, ribbed, enclosed by 

 the sp pals. Heads few. 



7. Sagittaria. Akenes in a head, flattened. Sepals reflexed, heads 

 few. 



Order 5. GRAMINEAE. 



Usually a caryopsis, (sometimes the seed is free from the pericarp), 

 enclosed within 2 scales, the upper scale, next to the axis, is 2-keeled on 

 the back, while the lower is 1 -nerved or keeled in the middle of the back, 

 or convex. The flowers or fruits are usually in 2-ranked clusters, with 

 a pair of empty scales at the base of the cluster. Herbs with 2-ranked 

 leaves. A large order with numerous genera and species. 



Order 6. CYPERACEAE. 



An Akene in the axis of a bract, often surrounded by bristles or a 

 sac, but no bract between the fruit and the axis, Fruits usually gather- 

 ed in spikes or heads. Herbs with 3-ranked leaves. 



