224 HALORAGIDACEAE 



8. GAURA L. 

 1. Gaura biennis L. Bienniai, Gaura. (Man. p. 663 ; I. F./. 260^.) 

 In dry soil, Quebec and Ont. to Minn., Ga., Neb. and Ark. — Pennsyl- 

 vania : Northampton ; Bucks ; Philadelphia ; Delaware ; Ches- 

 ter ; Lancaster ; Dauphin ; Franklin ; Washington ; Allegheny. 



9. CIRCAEA L. 



Leaf-blades mainly of an ovate type : fruit 2-celled. i. C. Luteiiana. 



Leaf-blades mainly of a cordate type : fruit i-celled. 2. C. alpina. 



1. Circaea Lutetiana L. Enchanter's Nightshade. (Man. p. 

 664 ; I. F. /. 2bio.) In woods, N. S. to W. Ont., S. Dak., Ga., Neb. 

 and Kans. Also in Eu. and Asia. — Pennsylvania : Pike ; Lackawanna ; 

 Tioga ; Northampton ; Bucks ; Delaware ; Chester ; Lancj^ster ; 

 Franklin ; Columbia ; Erie ; Allegheny. 



2. Circaea alpina L. Smaller Enchanter's Nightshade. (Man. 

 p. 664; I. F. y. 2611.) In cold, moist woods. Lab. to Alaska, Ga., Ind., 

 Mich, and S. Dak. Also in En- and Asia. — Pennsylvania : Pikb ; Lack- 

 awanna ; Tioga ; Sullivan ; Monroe ; Northampton ; York ; 

 Huntingdon ; Blair ; Cambria. 



Fam. 4. HALORAGIDACEAE Kl. & Garcke. Water Milfoil 



Family. 

 Flowers perfect : floral whorls of 3 parts : fruit mostly 3-celled. 



I. Proserpinaca. 

 Flowers monoecious or polygamous : floral whorls of 4 or 8 parts : fruit of 4 

 carpels. 2. Myriophyllum. 



1. PROSERPINACA L. 



Fruit sharp-angled : emersed leaves with toothed blades. i. P. palustris 



Fruit blunt-angled : emersed leaves with pectinate-pinnatifid blades. 



2. P. pectinata. 



1. Proserpinaca paltistris L. Mermaid-wbed. (Man. p. 665; I. 

 F. /. z6/j.) In swamps, N. B. to Lake Huron, Fla., Iowa and C. Am. 

 Also in Cuba. — Pennsylvania : Northampton; Bucks ; Dauphin ; Lu- 

 zerne, Lily Lake ; Huntingdon ; Erie. 



2. Proserpinaca pectinata Lam. CuT-lEaved Mermaid-weed. 

 (Man. p. 665 ; I. F. f. 2616.) In sandy swamps near the coast, eastern 

 Mass. to Fla. and La. — Pennsylvania : LANCASTER. 



2. MYRIOPHYLLUM L. 



Fruit of smooth keellfiss carpels. 

 Flowers only on emersed stems. 

 Bracts longer than the flowers, pinnatifid. i. M. verticillatum. 



Bracts shorter than the flowers, not pinnatifid, sometimes obsolete. 

 Submerged stems leafy : fruit 2 mm. long. ■£. M. spicatum. 



Submerged stems leafless or nearly so : fruit i mm. long. 



3. M. tenellum. 

 Flowers on both emersed and submerged stems. 4. M. humile. 



Fruit of 2-keeled carpels. 5. M. heUrophyllum. 



