Ty PHAGES. 219 



cleft in the edge of the frond, or from the upper surface. 

 Fruit a l-7-s6eded titriole. The flowers are rarely to be 

 seen. 



Synopsis of the Genera. 



1. I/ein'iia. Flowers from a cleft in the edge of the frond, usually 2 of 



a single stamen each, and 1 of a simple pistil, the three surrounded 

 by a spathe. Boots several or only one. 



2. WoIIT'ln. Floivers from the centre of the upper surface of the 



frond, only 2 ; one of a single stamen, the other of a simple pistil. 

 Roots none. The smallest of flowering plants. 



1. lili;:tl?rA, L. Duckweed. 



1. L. polyrrhl'za, L. (Spirodela polyrrhiza, Schleiden.) 

 Fronds round-obovate, green above, purplish beneath, mostly 

 7-nerved. Mootlets several. — Common in ponds and pools. 



2. L. tFisuI'ea, L. Fronds oblong to oblong-lanceolate, 

 half an inch or more long, narrowed at the base into a 

 slender stalk, denticulate at the tip, obscurely 3-nerved. 

 Rootlet single, often wanting. — Ponds and springy places. 



3. L. minor, L. Fronds round to elliptic-obovate, very 

 small. Rootlet sintjle. — Stagnant waters. 



a. WOMF'IA, Horkel. 



1. W. Columbia'na, Karsten. Globular or nearly so, 

 light green all over, not dotted. — Stagnant waters, usually 

 rather below the surface. 



'2. W. Bpasilien'sis, Weddell. Oblong, deep green above, 

 pale below, dotted all over with brown. — With the last, but 

 floating. 



Okder XCVI. TYPHA'CE.ffi. (Cat-tail Family.) 



Aquatic or marsh herbs with linear sword-shaped leaves, 

 erect or floating, and monoecious flowers, either in separate 

 heads or on different parts of the same spike or spa,dix, but 

 without a spathe, and destitute of true floral envelopes. 

 Fruit an achene, 1-seeded. 



Sfuopsis of (he <jonera. 

 1. Tyi>lia. Flowers in « very dense and long' cylindrical terminal 

 spike, the upper ones staminate, the lower pistjlldte, the gvavies 



