Loosestrife Family. 55 



solitary or several together; fruit sharply angled. Ponds; July; rather rare; 

 Muscatine, Story, and Boone counties. 



CALLITRICME L Leaves spatulate or linear, opposite. Flowers monoe- 

 cious, 1-3 together, axillary, sessile. Sepals and petals wanting. Sterile 

 flowers with one stamen; anther cordate, 4-celled, becoming 1-celled. Ovary 

 4 celled. Styles 2, distinct. Fruit nut-like, 4-lobed, 4-celled, membranous, 

 indehiscent. 



C. verna L. Perennial; floating leaves tufted, obovate, 3-nerved, narrowed 

 into a petiole; submerged leaves linear; flowers usually between a pair of 

 bracts; fruit ovate, styles shorter than the fruit. In a slough near Cedar riv- 

 er, Muscatine county; June-September. (C. palustrls L.) 



C. hetercphylla Pursh. Similar to the preceding species; floating leaves 

 broadly spatulate, often retuse, narrowed into a petiole; fruit obovate; styles 

 longer than the fruit. Wet slough; Jury; infrequent; Decatur county. 



MELASTOMACEAE R. Br. Meadow-Beauty Family. 

 Herbs with opposite parallel- veined leaves and perfect regular cymose 

 flowers. Petals inserted on the calyx-throat, alternate with the calyx- 

 lobes, stamens inserted with the petals, double their number; anthers 

 opening by pores at the apex. Represented with us by the genus Rexia 



L. 



R. Virginica L. Meadow-Beauty. Stem 1-2 feet high, square, angles some- 

 what winged, rootstock tuberiferous; leaves with 3-5 nerves, sessile, acute, 

 oval-lanceolate, nerves and margin more of less bristly; flowers peduncled, 

 bright, purple; calyx persistent 4-cleft, lower portion of the tube coherent 

 with the ovary, the upper free; petals 4; stamens 8; anthers long-linear, 1- 

 celled with a short spur near the filament; fruit a capsule, 4-celled, with 4 

 placentee from the central axis, many-seeded. In swampy places along Cedar 

 river; July; Muscatine county. 



LYTHRACEAE Lindl. Loosestrife Family. 



Herbs with mostly opposite entire exstipulate leaves and axillary or 

 whorled flowers. Calyx free from the ovary but enclosing it, persistent 

 4-7-toothed. Petals inserted on the top of the calyx-throat, equal in 

 number to the calyx-teeth, deciduous. Stamens 4-14, inserted on the 

 calyx-tube. Style 1; stigma capitate. Capsule 2-4-celled, with axial 

 placentas, many-seeded. 



* Flowers regular. 



Lythrum. Flowers rarely solitary ;,calyx tabular; petals usually 6. 

 Ammannia. Flowers solitary; calyx globular; peials and stamens usually 4. 

 Rotah. Flowers solitary; sinuses of the calyx appendaged ; petals and stamens 4. 

 DiDiPLis. Flowers solitary ; petals none ; stamens 4. 



* * Flowerti irregular. 

 Cuphea. Calyx more or less spurred; petals 6; stamens 11 or 12. 



LYTHRUM L. Leaves opposite or scattered, sessile. Flowers purple, 

 solitary axillary. Calyx tubular, striated, 5-toothed, with appendages in the 

 sinuses. Petals 5-7. Stamens 5-14. Capsule oblong, 2-celled. 



L alatum Pursh. Wing-angled Loosestrife. Perennial, smooth; stem 1-3 

 feet high with many long slender branches; leaves oblong-ovate to linear- 

 lanceolate, acute, base rounded or cordate, the upper mostly alternate; petals 

 deep purple; stamens of the short styled flowers exserted. Rich soil; July- 

 August; common. 



AMMANNIA L. Low smooth herbs, with opposite narrow leaves, and sub- 



