8 NAIADACEAE 



1. TYPHA L. CAT-TAIL. 

 Possessing the family characteristics as given above. 



Btarainate and pistillate flowers separated. 1. 7. angustifolia. 



Staminate and pistillate flowers not separated. 2. T. laiifolia. 



1. T. angustifolia L. Like the next but with narrower leaves and 

 spikes : pollen grains single. Ponds near Courtney and Independence- 

 Eare. June-July. 



2 T. latifolia L. 3-10 high : leaves 3"- 10" broad : staminate and 

 pistillate portion of spike contiguous, each from 3 / -l2 / long, and often an 

 inch or more in diameter : pollen grains in fours. Swampy grounds 

 throughout the county. Often common. June. 



FAMILY 9. SPARGANIACEAE Agardh. 



Marsh plants with general aspect of the last family but flowers in 

 widely separated heads in a branching inflorescence. Staminate heads 

 uppermost, conspicuously white. Perianth formed of from 3-6 irregular 

 scales. Filaments usually five, distinct. Ovary sessile, 1-2-celled, with 

 as many styles. Fruit usually 1-celled, very hard. 



1. SFARGANIUM L. 



Characters of the family. 



Fruit truncate at apex. 1. 8. turycarpum. 



Fruit tapering at apex. 2. S. androcladum. 



1. S. eurycarpum Engelm. BIG BUR-REED. Stems 2 L1 -8 high, with 

 long, slightly keeled, flat leaves : pistillate heads 2-6, KXM6" in diam- 

 eter at maturity : nutlets sessile, broad and truncate, many-angled. 

 Locally abundant. In swamps at Lake City, Buckner, and west of Sib- 

 ley. June. 



2. S. androcladum (Eagelm.) Morong. SLENDER BUR-REED. Re- 

 sembles the last but smaller throughout : nutlets stalked, fusiform. Wet 

 grounds three miles west of Sibley. Local. June. 



FAMILY 10. NAIADACEAE Lindl. 



Aquatic herbs with leafy stems and perfect or unisexual flowers. 

 Perianth of four segments or wanting. Stamens 1-4, hypogynous and 

 distinct in the fertile flowers, and with extrorse anthers. Ovaries one or 

 four, one-ovuled. 



Flowers perfect, ovaries four. 1. POT AMOG ETON. 



Flowers not perfect, ovary one. 2. NAIAS. 



1. POTAMOGETON L. PONDWEED. 



Herbs floating in still water or growing in the mud with two ranked 

 alternate or imperfectly opposite leaves. Flowers borne on usually 

 emersed spikes. Sepals, stamens and pistils four each. Sepals rounded 



