A GUIDE AND KEY TO AQUATIC PLANTS 131 



3. H. americana L. — Present in our area in North Carolina and 

 Tennessee. 



4. H. ranunculoides L. f.— Range includes all of our area. The 

 senior writer has observed it in alkaline waters near the coast. 



3. Centella L. 



C. erecta (L. f.) Femald —Shallow ponds and low places, Coastal 

 Plain, Florida north and west to beyond the limits of our territory. 

 Small's Manual gives this as C. repanda (Pers.) Small. 



4. Cicuta L. 



1. Fruit grooved at the junction of the carpels 1. C. curtissii. 



1. Fruit not grooved at the junction of the carpels 2. C. maculata. 



1. C. curtissii Coult. & Rose— Swamps in the Coastal Plain, 

 Florida north and west to beyond the limits of our territory. 



2. C. maculata L. — Swamps, mostly in the western part of our 

 territory. 



5. Sium [Tourn.] L. 



5. suave Walt. — Uncommon in ponds, marshes, and swamps over 

 most of our area. Small lists this as S. cicutaefolium Schrank. 



6. Ptilimnium Raf. 



1. Leaves simple, round 1 



1. Leaves compound, with narrowly linear segments. 



2. Fruit 2 mm. long or more; if only 2 mm. long 



sepals deltoid. 

 2. Fruit 1.5 mm. long or less; sepals lanceolate to 

 subulate. 



3. Sepals deltoid; fruit about 2 mm. long 



3. Sepals lanceolate to subulate; fruit 3-4 mm. long 



1. P. nodosum (Rose) Mathias — KJnown only from ponds on the 

 Coastal Plain, Southwest Georgia. 



2. P. nuttallii (DC.) Britton — Swamps in our region from Alabama 

 westward. 



3. P. capillaceum (Michx.) Raf. — Published range includes all of 

 our area, but probably most common in w^et areas along the coast. 



4. P. costatum (EU.) Coult. & Rose — Coastal Plain swamps, Georgia 

 to North Carolina. 



7. Oxypolis Raf. 



0. filijormis (Walt.) Britton — Acid low pinelands and shallow ponds 

 and swamps. Coastal Plain, Florida to South Carolina and westward 

 to beyond the limits of our range. 



