116 PUBLIC HEALTH BULLETIN NO. 2 86 



CERATOPHYLLACEAE Hornwort family 



1. Ceratophyllum L. 



1. Achene armed on the edges with spines, long-beaked.. 1. C. demersum. 

 1. Achene unarmed, short-beaked 2. C. submersum. 



1. C. demersum L. Coontail-moss — Various provinces, over all of 

 our territory. Most often found in neutral or alkaline waters, although 

 tolerating some degree of acidity. Anopheles guadrimaculatus has 

 been found associated with it. Variety echinatum A. Gray is sometimes 

 given specific rank. 



2. C. submersum L. — Found only in ponds on the southern part of 

 the peninsula of Florida. 



NIMPHAEACEAE Water-lily famUy 



1. Nuphar Sibth. 



1. Leaf-blades more than twice as long as wide, the sinus 2. 



less than one-fourth the length of the blade. 

 1. Leaf-blades less than twice as long as wide, the sinus 3. 

 one-fourth to one-half the length of the blade. 



2. Leaf-blades over 3 times as long as wide, the 1. N. sagittaefolia. 



sinus open. 

 2. Leaf-blades less than 3 times as long as wide, 2. A^. ulvacea, 

 the sinus closed. 



3. Leaves pubescent beneath 4. 



3. Leaves glabrous beneath 5. 



4. Leaf-blade with a closed sinus; stamens in 9-10 3. N. orbiculata. 

 rows; flowers about 5 cm. in diameter; seed 

 4 mm. long. 

 4. Leaf -blade with an open sinus; stamens in 6-7 4. A^. bombycina. 

 rows; flowers about 7 cm. in diameter; seed 6 

 mm. long. 



5. Leaf-blades of an orbicular or ovate-orbicular type 5. N. fluviatile. 



5. Leaf-blades manifestly longer than wide 6. 



6. Leaf-blades very thin; submersed leaves present- 6. N. chartacea. 

 6. Leaf-blades thick; submersed leaves absent 7. N. advena. 



1. N. sagittaefolium (Walt.) Pursh. Cow-lily- — Sluggish streams, 

 Coastal North and South Carolina and Virginia. This and the follow- 

 ing six species are all listed by Small under Nymphaea. 



2. N. ulvaceum (Miller & Standley) Standley — Sluggish streams 

 in West Florida. Possibly this is what has been recorded as N. 

 sagittaefolium from Alabama. 



3. N. orbiculatum (Small) Standley — Lakes and ponds from Middle 

 Florida to Southernmost Georgia. 



4. N. bombycinum (Miller & Standley) Standley — Ponds in the 

 Coastal Plain, North Florida and adjacent Georgia. The senior 

 author has collected it from acid limesinks in South Georgia, near 

 the South Carolina line. 



