ONAGRACEAE 221 



3. LYTHRUM L. 



Flowers solitary in the axils : stamens not more than the petals. 



Annual : flowers not dimorphous: stamens included. i. L. hyssopifolinm. 

 Perennial : flowers dimorphous : stamens of short-styled flowers exserted. 



2. L. alatunt. 

 Flowers in panicled terminal spikes : stamens twice as many as the petals. 



3. L. Salicaria. 



1. Lythrum hyssopifolium Iv. Hyssop Loosestrife. (Man. p. 649 ; 

 I. F.yi ^5-/5- ) Borders of salt marshes, Me. to Pa. and N. J. Also in Calif, 

 and S. Am. Nat. from Eu. — Pennsylvania : Bucks, Plumsteadville. 



2. Lythrum alatum Pursh. Wing-angled Loosestrife. (Man. p, 

 650; I. F. y. 2^^b.) In low grounds, southern Ont. to Mass., Ky., S. 

 Dak. and Kans. — Pennsylvania : Delaware, Hay Island ; Allegheny. 



3. Lythrum Salicaria L. Spiked or Purple Loosestrife. (Man. 

 p. 650 ; I. F.y. 2^4g.) In swamps and wet meadows, Cape Breton Island 

 to Ont. and Del. Said to be nat. from Eu. — Pennsylvania : Northamp- 

 ton ; Bucks ; Philadelphia ; Chester ; Allegheny. 



4. PARSONSIA P. Bi'. 

 1. Parsonsia petiolata (L.) Rusby. Blue Wax-weed. Clammy 

 CUPHEA. (Man. p. 650; I. F. f. 2350.) In dry soil, R. I. to 111., Kans., 

 Ga. and La. Introd. into southern Ont. — Pennsylvania : Northampton ; 

 Bucks ; Philadelphia ; Delaware ; Chester; Lancaster; Leba- 

 non ; Dauphin ; Franklin ; Huntingdon ; Allegheny. 



Family 3. ONAGRACEAE Dumort. Evening-primrose Family. 



Floral whorls of 4 parts or more. 



Fruit a many-seeded capsule, opening by valves or a pore. 

 Hypanthium not prolonged be5'ond the ovary. 

 Seeds naked. 



Leaves opposite : plants with creeping or floating stems. 



1. ISNARDIA. 



Leaves alternate : plants with erect or ascending stems. 



2. LUDWIGIA. 



Seeds with tufts of hairs. 3. Chamaenerion. 



Hypanthium prolonged bej'ond the ovary. 

 Seeds furnished with tufts of hairs. 4. Epilobium. 



Seeds naked, sometimes tuberculate. 

 Stamens equal in length. 

 Ovules and seeds horizontal, angled. 5. Onagra. 



Ovules and seeds ascending, not angled. 6. Oenothera. 



Stamens unequal in length, the alternate ones longer. 



7. Kneiffia. 

 Fruit indehiscent, nut-like. 8. Gaura. 



Floral whorls of 2 parts. 9. Circaea. 



1. ISNARDIA L. 



1. Isnardla palustris L. Marsh Purslane. (Man. p. 652 ; I. F. /. 



^5SS-) In muddy ditches and swamps, N. S. to Man., Ore., Fla., Calif, 

 and Mex. — Peftnsylvania : Northampton ; Bucks ; Monroe ; Dela- 

 ware ; Chester ; Lancaster ; Franklin ; Erie ; Allegheny. 



