EPILOBIACEAE. 203 



2. LUDWIGIA L. Annual or perennial herbs. Leaf -blades narrow, entire 

 or rarely shallowly toothed. Flowers axillary or terminal. Sepals generally 

 persistent. Petals usually 4. Ovary usually 4-celled. Capsule cylindrie or 

 prismatic to globose. — False-loosestrife. 



1. L. alternifolla L. Plants 6-12 dm. tall: leaf -blades lanceolate, 6-12 cm. 

 long: sepals ovate: petals about equalling the sepals: capsules slightly winged 

 on the angles, 5-7 mm. long. — Common, in wet places. — Sum. — Seedbox. 



3. CHAMAENERION Adans. Perennial herbs. Leaf-blades entire or 

 nearly so. Flowers irregular, in showy racemes. Sepals 4, deciduous. Petals 

 4, entire. Stamens 8, declined. Stigmas 4. Capsule elongate, obtusely angled. 

 Seeds comose. 



1. C. angustifolium (L.) Scop. Plants 5-25 dm. tall, often clustered: leaf- 

 blades lanceolate, 5-15 cm. long: corolla purple or sometimes white; petals 

 1-1.5 cm. long: capsules 5-7.5 em. long: coma of seeds about 10 mm. long. — 

 Occasional, in woods and thickets and on hillsides. — Sum. — Fire-weed. 

 Willow-herb. 



4. EPIIiOBIUM L. Perennial herbs or somewhat woody plants. Leaf- 

 blades entire or toothed. Flowers solitary, spicate, or racemose. Sepals 4, 

 short, deciduous. Petals 4, pink or white, often notched. Stamens 8. Stigmas 

 4, or united and clavate. Capsules elongate, 4-sided. Seeds comose. — Sum. 

 and fall. — Willow-herb. 



Stem and branches terete : leaf-blades linear to lanceolate, revolute, essentially- 

 entire. 

 Corolla small, about 1 cm. wide : leaf-blades petioled : plants canescent. 



1. E. Uneare. 

 Corolla large, about 1.5 cm. wide : leaf-blades sessile : plants 



glandular-pubescent. 2. E. strictum. 



Stem and branches with decurrent ridges below the leaf-bases : 



leaf-blades ovate to lanceolate, flat, serrate. 3. E. coloratum. 



1. El. lineare Muhl. Plants 3-5 dm. tall: leaf -blades linear or nearly so, 2.5-5 

 cm. long : flowers erect : sepals 2-3 mm. long : petals 4-5 mm. long, shallowly 

 notched: capsules 3.5-5.5 cm. long: seeds about 1.5 mm. long. — S. Eare, in 

 moist grounds. — Schists. 



2. E. strictum Muhl. Plants 3-9 dm. tall: leaf -blades lanceolate to linear, 

 1.5-4 cm. long, entire or obscurely toothed, veiny, sessile: sepals 3-4 mm. long: 

 petals cuneate, about 8 mm. long, deeply notched: capsules 5-7 cm. long: seeds 

 about 2 mm. long. — M. Rare, Dillerville swamp, Lancaster. — Limestones. 



3. E. coloratum Muhl. Plants 3-9 dm. tall: leaf -blades lanceolate, 5-15 cm. 



long: flowers generally nodding: sepals 2.5-3.5 mm. long: petals 3-4 mm. long, 

 shallowly notched : capsules 4.5-6 cm. long. — Common, in low grounds. 



5. OENOTHEEA L. Annual or biennial large herbs. Leaf -blades undu- 

 late or toothed. Buds erect. Flowers nocturnal, spicate. Sepals elongate. 

 Corolla yellow. Capsules 4-sided, tapering. [Onagra Adans.] — Sum. — Even- 

 ing-primrose. 



Sepals less than 3 cm. long, the free tips subulate, less than 4 mm. long : corolla 



2-5 cm. wide. 1. O. biennis. 



Sepals over 3 cm. long, the free tips filiform, over 5 mm. long : 



corolla 8-12 cm. wide. 2. O. rjrandiflora. 



1. O. biemils L. Stems 13-25 dm. tall, hirsute: leaf -blades oblong to lanceo- 

 late, 2.5-15 cm. long, repand-denticulate : petals bright-yellow, 1-2.5 cm. long: 

 capsules narrowly oblong-conic, 18-25 mm. long, nearly terete. — Common, on 

 roadsides and in thickets. 



