ORDER 52. ONAGRACKdE. 357 



1 to 2' long, f as wide, acute or acuminate, with small, remote teeth, pale green 

 and shining. Fls. white, rarely reddish, minute, in terminal racemes. JL 



9. PROSERPINA'CA, L. MERMAID WEED. (Lat. Proserpina, a 

 Roman goddess; from some fancied resemblance.) Calyx tube ad- 

 herent to the ovary, 3-sided, limb 3-parted ; petals none ; stamens 3 ; 

 stigmas 3 ; fruit 3-angled, 3-celled, bony, crowned with the permanent 

 calyx. ~4 Aquatic. Lvs. alternate. 



1 P. palustris L. Lvs. linear-lanceolate, sharply serrate above the water, those 

 below (if any) pinnatifid. Ditches, swamps and ponds, often partly submerged, 

 N. Eng., Fla. and La. Rt creeping. Sts. ascending at base, 6 to 20' high, 

 striate, roundish. Lvs. 10 to 15 ' by 2 to 3", acute at each end, lower ones on 

 short petioles and, if growing in water pinnatifid with linear segments. Fls. 

 greenish, sessile, 1 to 3 together, in the axils of the upper leaves, succeeded by 

 a very hard, triangular nut. Jn., Jl. 



2 P. pectinacea Lam. Lvs. all pectinate, with linear-subulate segm. ; fr. obtusely 

 3-angled. Sandy swamps, in Mass, (rare) S. to Fla. St. 5 to 10' high, afecending 

 at base from long, creeping roots. Lvs. all finely and regularly divided into very 

 narrow segments. Sty. ; stig. attenuate above. Fr. rather smaller (less than 

 1" diam.) than in P. palustris, rugous when mature. JL, Aug. 



10. MYRIOPHYL'LUM, Vaill. WATER MILFOIL. (Gr. ftvpiog, innu- 

 merable, 0uAAa, leaves.) Flowers 8 , or frequently ; calyx 4-toothed 

 in the and ? flowers, 4-parted in the o ; petals 4, often inconspicu- 

 ous or none ; stamens 4 to 8 ; stigmas 4, pubescent, sessile ; fruit o 4, 

 nut-like carpels, cohering by their inner angles. H submersed, aquatic 

 herbs. Submersed Ivs. parted into capillary segments. Upper fls. usu- 

 ally $ , middle ones , lower ? . 



Stamens 8. Carpels smooth and even. Leaves whorled in 3s Nos. 1, 2 



Stamens 4. Carpels ridged on the back. Lvs. whorled in 4s and 5s Nos. 8, 4 



Carpels smooth and even. Lvs. alternate or wanting Nos. 5, 6 



1 M. spicatum L. Lvs. hi verticils of 3s, all pinnately parted into capillary seg- 

 ments; fls. in, terminal, nearly naked spikes; floral Ivs. or bracts, ovate, entire, 

 shorter than the fls., lowest ones subserrate and larger; petals broadly ovate; 

 stam. 8 ; carp, smooth. N. Eng. to Ark., in deep water, the fls. only rising above 

 the surface. St. slender, branched, very long. Lvs. composed of innumerable, 

 hair-like segments, always submerged. Fls. greenish, sessile. Jl., Aug. 



2 M. verticillatum L. Lvs. in verticils of 3s, lower ones pinnately parted into 

 opposite, capillary or setaceous segments ; fls. in terminal, leafy spikes ; floral Ivs. 

 pectinate-pi nnatifid, much longer than the fls. ; petals oblong-obovate ; stam. 8 ; 

 carp, smooth. In stagnant water, Can. to Fla., "W. to Or. St. long, less slender 

 than in the last, only the upper part emerging. Fls. small, green, axillary, with 

 conspicuous floral Ivs. Sep. acute. Anth. oblong. Jl., Aug. 



3 M. heteroph^llum MX. Lvs. in verticils of 5s, the lower ones pinnately 

 parted into capillary lobes; spikes terminal, nearly naked; floral Ivs. ovate-lanceo- 

 late, serrate, longer than the fls., crowded; petals oblong; stam. 4 to 6; carp, 

 scabrous, with 2 slight ridges on the back. In sluggish water, Can. to Fla. and 

 Tex., rare. St. thick, branching. Lvs. very various, lowest floral ones pecti- 

 nately divided. Petals somewhat persistent. Sepals minute. Bractlets serrulate. 

 Jn. Sept. 



4 M. scabratum MX. Lvs. pinnatifid in whorls of 4s and 5s ; fls. verticillate, 

 axillary, upper fls. $ , with 4 stam., lower ones 2 ; floral Ivs. linear, pectinately 

 toothed ; fr. 8-angled, the ridges tuberculate. Plymouth, Mass. (Oakes), Block 

 Island (Robbins), S. and W. States. St. 6 to 12' high. Segm. of the Ivs. linear- 

 capillary. 



5 M. tenellum Bw. Erect and almost leafless; floral Ive. or bracts alternate, 

 minute, entire, obtuse ; fls. ft ; petals linear ; stam. 4 ; carp, smooth, not ridged. 

 About the edges of ponds and rivers, Providence, R. I. (OlneyX northern part of 



