A GUIDE AND KEY TO AQUATIC PLANTS 129 



HALORAGIDACEAE Water milfoil family 



1. Proserpinaca L. 



1. Leaves all nearly alike and all deeply lobed or divided-- 2. 



1. Upper leaves (those bearing flowers in axils) toothed 1. P. palustria. 

 but not lobed or divided. 



2. Rachis of leaves about as broad as the segments- 2. P. pectinata. 



2. Rachis of leaves much broader than the seg- 3. P. intermedia. 

 ments or lobes. 



1. P. palustris L. Mermaid Weed — This species is found Ln our 

 region in several varieties, and it includes not only P. palustris but 

 also P. amhlygona and P. platycarpa of Small's Manual. The range 

 of the species covers all of our territory, and it is often found in acid 

 situations but shows some tolerance. 



2. P. pectinata Lam. — ^Ranges over all of our area, but most com- 

 mon in the Coastal Plain. Found in the same type places as the 

 preceding species. 



3. P. intermedia Mackenzie — Possibly a hybrid between the two 

 preceding. Rare but known from Georgia north to beyond the 

 limit of our territory. 



2. Myriophyllum L. 



1. Emersed leaves nearly like submerged leaves 1. M. braailiense. 



1. Emersed leaves definitely different from submerged 2. 

 leaves. 



2. Stamens 4; corolla persistent 3. 



2. Stamens 8; corolla deciduous 2. M.laxum. 



3w Floral (emersed) leaves with ovate, toothed blades 3. M. heterophyllum. 



3. Floral leaves deeplj- lobed or divided 4. M. pinnalum. 



1. M. brasiliense Cambess. Parrot 's-feather — Tropical species, 

 introduced in the Coastal Plain, Florida to Georgia and westward 

 beyond the limits of our territory. It is often found in association 

 with Anopheles quadrimaculatus and seems to prefer neutral or alkaline 

 waters. This species is listed under M. proserpinacoides Gill by Small, 



2. M. laxum Shuttlw.- — Rare species, found onlj^ ia ponds and lakes 

 in North Florida, South Georgia and South Alabama. The senior 

 writer has collected it from acid, open limesinks in Southwest Georgia. 



3. Af. heferophyllum Miclix. — Ranges over all of our territory, but 

 most common in the Coastal Plain. Seems to prefer less acid waters 

 than the following. Anopheles quadrimaculatus is often found associ- 

 ated witli it. 



4. M. pinnatum (Walt.) B. S. P. — Should range over all of our terri- 

 tory. It is the impression of the writers that this species is found in 

 more acid waters than the preceding, but owing to the difficulty of 

 identifying the Myriophyllum. group in the field this impression may be 

 erroneous. It is most common in the Coastal Plain. 



