LYTHRACEAE 137 



Flowers regular. 

 Stamens four. 



Petals none. 1. Didiplis. 

 Petals present. 



Leaves aurioulate or clasping. 2. Ammannia. 



I^eaves tapering at base. 3. Rot ALA. 



Stamens six to twelve. 4. Lytheum. 



Flowers irregular. 5. Paesonsia. 



1. DIDIPLIS Raf. 



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

 daged. Capsule globose, indehisoent, 2-celled. 



1. D. diandra (Nutt.) Wood. Watee Pueslane. 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-oelled, irregularly 

 dehiscent. 



Cymes sessile. 1. A. eoednea. 



Cymes plainly peduncled. 2. A. auriculata. 



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

 1-5 together : calyx vsith tour accessory teeth : petals purplish : styles 

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

 ^Y'-Z" 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 septioidal capsule, the valves mi- 

 nutely densely striate. 



1. R. ramosioT (L.) Koehne. Ascending, I'-IS' high : leaves spatu- 

 late or linear-oblong : flowers bi-braoteolate, 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 3-celIed. 



1. L. alatum Pursh. Loosbsteifb. 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. FARSONSIA P. Br. 



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

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

 seeded, dehiscent. 



