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1. Myriophyllum. Flowers monecious or polygamous, the parts in fours, with 
or without petals; stamens 4 or 8; leaves often whorled, the immersed ones pin- 
nately dissected. 
2. Proserpinaca, Flowers perfect, the parts in threes: petals none: leaves alter- 
nate, the immersed ones pinnately dissected, 
1. MYRIOPHYLLUM Vaill. (WaTER-MILFOIL.) 
Perennial aquatics, with crowded, often whorled leaves (those under 
water pinnately dissected into capillary divisions), sessile moncecious or 
polygamous flowers in the axils of the upper leaves, and a nut-like 
4-celled deeply 4-lobed fruit. 
1, M. heterophyllum Michx, Stem stout: leaves whorled in fours and fives; 
floral ones ovate and lanceolate, thick, crowded, sharply serrate; lowest pinnatifid: 
stamens 4: fruit obscurely roughened.—Reported from streams between the Perdi- 
nales and Eagle Pass, but doubtless widely distributed, 
2. PROSERPINACA L. (MERMAID WEED.) 
Low perennial herbs, with stems creeping at base, alternate leaves, 
small perfect tlowers sessile in the axils (solitary or 3 or 4 together) 
with parts in threes, and a bony 3-angled 3-celled 3-seeded nut-like 
fruit. 
1, P. palustris L. Leaves lanceolate, sharply serrate, the lower pectinate when 
under water: fruit sharply angled.—Reported from the Nueces and its tributaries, 
2. P. pectinacea Lam. Leaves all pectinate, the divisions linear-awl-shaped : 
fruit rather obtusely angled.—On the Perdinales, 
LYTHRARIEX, (LOOSESTRIFE FAMILY.) 
Mostly herbs, with mostly opposite entire leaves, no stipules, axillary 
or whorled flowers, calyx inclosing but free from the 1 to 4-celled many- 
seeded ovary and membranous capsule and bearing the 4 to 7 deciduous 
petals and 4 to 14 stamens on its throat, solitary style with capitate or 
2-lobed stigma. 
* Flowers solitary or clustered in the axils of the leaves, sessile or nearly so. 
1, Rotala. Calyx short, the sinuses appendaged: petals and stamens 4: capsule 
septicidal, with 3 or 4 valves. 
2, Ammannia. Calyx as in the last: petals generally 4 or none: stamens 4; cap- 
sule bursting irregularly. 
** Flowers solitary, but on distinct, often very long pedicels, 
3. Neszea. Petals generally 6: stamens 12 or 13, 
*** Flowers in 3 to many-flowered axillary cymes, 
4, Lythrum, Calyx tubular: petals usually 6: stamens mostly 6 or 12. 
1. ROTALA L. 
Low and smooth herbs, with short-campanulate or semiglobose calyx 
having tooth-like appendages at the sinuses, 4 petals, 4 short stamens, 
and a globular 4-celled septicidal capsule with the valves transversely 
and densely striate under a lens. 
