EVENING-PRIMROSE FAMILY. 141 



1 MYBTOPHYLLUM. Flowers mostly monracious 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. H11TUK1S. 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. 2/ 



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 % ; 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. ; with 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. : with 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- 

 ser/>o, to creep, or after Proserpine.) Stems creeping at base in the mud or 

 shallow water, the upper part emerging : flowers in the axils of the alternate 

 leaves, produced all summer. 2/ 



P. palilStris. Leaves above water 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 (which the botanical name means in 

 Greek). 



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

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

 flowers in their axils. ^/ 



44. ONAGRACE^S, EVENING-PRIMROSE FAMILY. 



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

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

 the tube of the calyx usually prolonged more or less beyond the 

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

 petals (convolute in the buH) 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. Paris of the flower in twos. 



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

 whitish flowers in racemes. Calyx with 2 reflexed lobes, its tube VliplHv 

 prolonged beyond the 1-2-celled ovary, which becomes n. 1-2-seeded littlo 

 bur-like indehiscent fruit, covered with wpak hooked bristles. Petals 2, ob- 

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



