LYTHRACEAE 137 



Flowers regular. 

 Stamens four. 



Petals none. 1. DIDIPLIS. 



Petals present. 



Leaves auriculate or clasping. 2. AMMANNIA. 



Leaves tapering at base. 3. ROTALA. 



Stamens six to twelve. 4. LYTHRUM. 



Flowers irregular. 5. PARSONSIA. 



1. DIDIPLIS Raf. 



Aquatics with linear leaves. Calyx hemispheric, 4-lobed, not appen- 

 daged. Capsule globose, indehiscent, 2-celled. 



. 1. D. diandra (Nutt.) Wood. WATER PURSLANE. 2 / -10 / long : 

 flowers small. In ponds at Lake City and Sibley. Common at times. 

 July-October. 



2. AMMANNIA L. 



Flowers in axillary cymes. Calyx globular, 4-angled, 4-toothed, 

 often with accessory teeth. Capsule globular, 2-4-celled, irregularly 

 dehiscent. 



Cymes sessile. 1. A. coccinea. 



Cymes plainly peduncled. 2. A. auriculata. 



1. A. coccinea Rottb. 4 / -20 / high : leaves linear-oblong : flowers 

 1-5 together : calyx with four accessory teeth : petals purplish : styles 

 elongated, slender : pods oblong-orbicular, usually shorter than the calyx, 

 2 // -3 // high. Common on muddy banks throughout. 



2. A. auriculata Willd. Resembles the last but usually more slender 

 and branching : calyx usually without accessory teeth : capsules nearly 

 orbicular, exceeding the calyx, 2" high. In similar situations as the last, 

 and about as common. 



3. ROTALA L. 



Differs from Ammannia in having a septicidal capsule, the valves mi- 

 nutely densely striate. 



1. R. ramosior (L.) Koehne. Ascending, 1/-15' high : leaves spatu- 

 late or linear-oblong : flowers bi-bracteolate, usually solitary in the axils. 

 On muddy banks throughout. Not uncommon. June-September. 



4. LYTHRUM L. 



Calyx tube cylindric, 8-12-striate, with 4-7 teeth and as many appen- 

 dages. Petals 4-7, obovate. Capsules 2-celled. 



1. L. alatum Pursh. LOOSESTRIFE. Perennial, l-3 high, glabrous : 

 leaves ovate- lanceolate with a rounded base, acute, alternate or opposite : 

 flowers pinkish-purple, conspicuous. Common in low grounds. June- 

 September. 



5. PARSONSIA P. Br. 



Calyx 12-ribbed, gibbous at the base, oblique at the mouth, 12-toothed. 

 Petals 6, unequal. Stamens 11 or 12, unequal. Capsule 1-celled, few- 

 seeded, dehiscent. 



