EVENING-PRIMROSE FAMILY. 141 



1. MYRIOPHYLLUM. Flowers mostly monoecious, with sepals or teeth of the 



calyx, petals when there are any, lobes and cells of the ovary and nut-like 

 fruit, and the sessile stigmas each 4; the stamens 4 or 8. 



2. PROSERPINACA. Flowers perfect, with lobes of the calyx, stamens, stig- 



mas, and cells of the 3-angled nut-like fruit each 3: petals'none. 



3. HIPPURiS. Flowers mostly perfect, with truncate calyx not continued above 



the adherent ovary, and a single stamen, slender style', and seed. 



1. MYRIOPHYLLUM, WATER-MILFOIL. (Botanical name, from 

 the Greek, like the popular name, means thousand-leaved.) Plants usually 

 all under water, except their flowering tips ; all but the uppermost or emerg- 

 ing leaves pinnately dissected into fine hair-like divisions. Fl. summer. ^J 

 M. spicatum. Leaves whorled in threes or fours, those at the summit of 



flowering stems reduced to small ovate bracts shorter than the flowers, which 

 therefore form an interrupted spike ; petals deciduous ; stamens 8 ; fruit smooth. 



M. verticillatum. Like the first, but the uppermost leaves longer than 

 the flowers and pinnatifid. 



M. heteroph^llum. Chiefly W. & S. ; with leaves whorled in fours or 

 fives, those under the flowers ovate or lanceolate and serrate or merely pinnatifid ; 

 stamens and petals 4 ; fruit roughish on the back. 



M. SCabratum. Chiefly S. & W. ; Avith leaves and flowers as in the 

 preceding, but more slender, the leaves under the flowers linear and cut-toothed, 

 and the lobes of the fruit 2-ridged and roughened on the back. 



M. ambiguum. Common only E. : Avith mostly scattered very delicate 

 or capillary leaves, often perfect flowers, 4 petals and 4 stamens, and a minute 

 smooth fruit. 



2. PROSERPINACA, MERMAID-WEED. (Name from Latin pro- 

 serpo, to creep, or after Proserpine.) Stems creeping at base in the mud or 

 shalloAV Avatcr, the upper part emerging : flowers in the axils of the alternate 

 leaves, produced all summer. 2/ 



P. palustris. Leaves above Avater lanceolate and merely serrate ; fruit 

 sharply 3-angled. 



P. pectinacea. Leaves all pinnately divided into very slender divisions ; 

 angles of the fruit bluntish. Chiefly E. *S. 



3. HIPPURIS, MARESTAIL (Avhich the botanical name means in 

 Greek). 



H. vulgaris. In ponds and springs N. & W., but rare: stems l-2 

 high, the linear acute leaves in whorls of 8-12, the upper ones Avith minute 

 flowers in their axils. 2/ 



44. ONAGRACE^I, EVENING-PRIMROSE FAMILY. 



Herbs, or sometimes shrubs, without stipules ; the parts of the 

 symmetrical flowers in fours (rarely in twos to fives) throughout ; 

 the lube of the calyx usually prolonged more or le.^s beyond the 

 adherent ovary, its lobes valvate in the bud, its throat bearing the 

 petals (convolute in the bud) and the as many or twice as many 

 stamens ; styles always united into one. Embryo filling the seed : 

 no albumen. Comprises many plants with showy blossoms, culti- 

 vated for ornament; these almost all American. (Lopezia has 

 irregular flowers with only one perfect stamen.) 



1. Parts of tli e flower in twos. 



1. CIRCLE A. Delicate low herbs, with opposite thin leaves, and very small 

 whitish flowers in racemes. Calyx with 2 reflcxed lobes, its tube slightly 

 prolonged beyond the 1-2-celled ovary, which becomes a 1-2-seeded little 

 bur-like indehiecent fruit, covered with weak hooked bristles. Petals 2, ob' 

 cordate. Stamens 2. Style slender, tipped with a capitato stigma. 



