OUDER 52,-OXAGRACE^E. 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 somo 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. 2f Aquatic. Lvs. alternate. 



1 P. palustris L. Lvs. linear -lanceolate, sharply serrate alx>ve 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, ascending 

 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. pvptos, innu- 

 merable, <i>AAa, leaves.) Flowers 8 7 or frequently ; calyx 4-toothed 

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

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

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

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

 ally <$ , middle ones , lower ? . 



StamensB. Carpels smooth and even. Lenvcs whorled in 3s Nos. 1, 2 



35tamens 4. Carpels ridged on the back. Lvs. whorled in 4s and 5s Nos. 3, 4 



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



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

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

 shorter than tfie 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. verticillatrum L, Lvs. in verticils of 3s, lower ones pinnately parted into 

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

 pectinate-pinnatifld^ miich longer than Hie 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. heterophylhira 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 fis., 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. scabratnm MX. Lvs. pinnatifid in whorls of 4s and 5s; fls. verticillate, 

 axillary, upper fls. $ , with 4 stam., lower ones $ ; 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. tenellnm Bw. Erect and almost leafless; floral Ivs. or bracts alternate, 

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

 About the edges of ponds and rivers, Provideace, R, I. (Olney), northern part of 



