310 ORDER XLVII. — LYTHRACE^E. 



2. Calyx 6-toothed. ventricose Cuphea, 5 



Calyx with less than 6 teeth, not ventricose 8 



8. Calyx 4 — 6 teeth, cylindrical % . Lythrum, 3 



Calyx campanulate 4 



4. Calyx 4-lobed Ammannia, 2 



Calyx with 5 teeth Decodon, 4 



Genus I.— HYPOBRICH'IA. Peplis, 4—1. 



Calyx 4-lobed and sometimes with intermediate segments, 

 campanulate, apetalous. Stamens 2 — 4. Ovary 2-celled, glo- 

 bose. Stigma 2-lobed, nearly sessile. Capsule 2-celled, mem- 

 branaceous, dehiscing irregularly. Seeds numerous. Flowers 

 minute, axillary. An aquatic plant, with opposite, linear 

 leaves. 



1. H. Nuttal'lii, (L ) Stems leafy, immersed. Leaves numerous, 

 linear, acute, the uppermost shorter and broader, obtuse. Flowers very 

 small. Stamens 2 — 4, shorter than the calyx. — ©. July — xiug. In 

 still waters. 12 — 20 inches. Water Purslane. 



Genus II.— AMMAN'NIA. Houst. 4—1. 

 (In honor of John Ainmann.) 



Calyx 4-lobed, with 4 intermediate lobes produced in the 

 sinuses. Petals 4 or none. Stamens generally 4, sometimes 

 8. Ovary 2 — 4-celled. Capsule included in the calyx. Seeds 

 numerous. Stems square ; leaves opposite. Flowers axillary, 

 with small petals. Herbaceous, annual plants. Growing in 

 wet places. 



1. A. latifo'lia, (L.) Stem erect, branching. Leaves linear, lanceo- 

 late, dilated at the base, sessile. Flowers 1 — 5 in each axil. Calyx 

 angled, with 4 short, intermediate lobes. Petals 4. Stamens 4. Cap- 

 sule 4-celled. — Purple. 0. July — Aug. Near Macon. 10 — 20 in. 



2. A. ramos'ior, (Mich.) Stem erect, somewhat columnar, succulent, 

 glabrous. Leaves nearly sessile, narrow, lanceolate, more or less cor- 

 date. Flowers axillary, the lower ones several in each axil, the upper 

 solitary. Petals small. Stamens 4. Capsule globose, furrowed. Seeds 

 numerous. — Pale purple. 0. Aug. — Sept. Wet places. 1 — 2 feet. 



3. A. hu'milis, (Mich.) Stem erect, quadrangular, glabrous, some- 

 times branched. Leaves lanceolate, obtuse, tapering at the base. Flow- 

 ers solitary, axillary. Calyx with 4 short, intermediate segments. 

 Petals 4, obovate. Stigma capitate, nearly sessile. Capsule 4-celled. 

 Seeds numerous. — White. %. On the coast. Sept. — Oct. 6 — 10 in. 



Genus III— LY'THRUM. L. 11—1. 

 (From the Greek luthron, black blood, from the purple color of the flowers.) 



Calyx cylindrical, with 4 — 6 short teeth, and generally with 

 as many intermediate processes. Petals 4 — 6. Stamens equal, 

 or twice as many in number as the petals* inserted into the 



