56 ONAGRACEAE. 



sessile eymose axillary flowers. Calyx globular, 4-angled, 4-toothed; sinuses 

 with horn-like appendages. Petals 4, purplish, deciduous. Stamens 4-8. 

 Capsule globular 2-4-celled. 



A. coccinea Rottb. Stem 4-8 inches high, branched from below; leaves 

 linear-lanceolate; stamens more or less exserted; style slender, elongated. 

 Swampy places, shores; July-September; infrequent; Muscatine, Louisa, 

 Johnson, Decatur, Story, and Lyon counties. < 



FyOTALA L. Low herbs. Calyx semiglobose or campanulate; sinuses 

 with tooth-like appendages. Petals and stamens 4. Capsule globular, 4- 

 celled. 



F^. ramosior (L.) Koehne. Stem 5-6 inches high, smooth, simple; leaves 

 linear-oblanceolate, opposite, tapering to a petiole; flowers solitary, axillary, 

 sessile; appendages shorter or as long as the calyx-teeth. Low wet places; 

 July-September; infrequent; Muscatine, Henry, Benton, and Lyon counties. 



DIDIPLIS Raf. Aquatic or marsh plants, with opposite leaves, 4-angled 

 stems, and mostly solitary axillary flowers. Calyx 4-lobed, appendages none. 

 Petals wanting. Stamens usually 4, inserted on the calyx-tube. Capsule 

 globose, 2-oelled. 



D. linearis Raf. A low glabrous much branched plant, 2-6 inches long; 

 leaves long-linear or lanceolate, mostly sessile; flowers small, greenish; calyx- 

 lobes broad, triangular; style short; capsule small. Mud flats, shallow 

 water; June-August; infrequent; Decatur and Ringgold counties. (D. 

 diandra (Nutt.) Wood.) 



CUPrJEA P. Br. Herbs, with opposite or verticillate leaves, and axillary 

 irregular unsymmetrical flowers. Calyx tubular, gibbous or spurred at the 

 base, apex 6-toothed, with 6 appendages, mouth oblique. Petals 6, unequal. 

 Stamens 11 or 12, inserted on the throat of the calyx, unequal. Capsule ob- 

 long, included, 1-celled, dehiscent. 



C. Viscosissima Jacq. An erect viscid-pubescent annual, 6-20 inches high, 

 branched; leaves ovate-lanceolate, slender petioled, apex bluntish, base 

 rounded; flowers purple, axillary, short-peduncled; petals ovate, clawed. 

 Dry soil: July-September; reported as belonging to the flora of Iowa by 

 Arthur. (Parsonia petiolata (L.) Rusby.) 



ONAG-RACEAE Dumort. Evening-primrose Family. 

 Herbs, with alternate or opposite leaves, and perfect symmetrical 

 flowers. Calyx herbaceous or colored, of 4 lobes, rarely less, valvate in 

 the bud, tube cohering with the ovary. Stamens as many or twice as 

 many as the petals and inserted with tbem on the top of the calyx- 

 throat; anthers 2-celled, introrse; pollen grains often cohering by threads. 

 Ovary inferior, 4-celled. Fruit a 2-4-celled many-seeded capsule. 



* Parts of the flower in fours. 



f Calyx-tube not -prolonged beyond the swmmit of Hie ovary; fruit dehiscent. 

 Ludwjgia. Leaves opposite or alternate, stamens 4; capsule short, 

 f f Calyx-tube prolonged beyond the summit of the ovary; fruit deliiscent. 

 Epllobiom. Leaves often opposite ; seeds silky tufted. 

 Oenothera. Leaves alternate; needs naked. 



f t t Fruit indehiscent. 

 Gauha. Filaments appendaged at the hase; fruit indehiscent. 



* * Parts of the flower in twos. 

 Cikcaea. Sepals, petals, and stamens 2; fruit bristly. 



