Myriophyllum. LV. ONAGRACEiE. 267 



delicate plant, common in wet, rocky woodlands in mountainous districts, N. 

 Eng., Brit. Am. W. to Or. Stem diaphanou.^, juicy, 5 — 10' hif?h. Leaves 1 — 

 2' long, § as wide, acute or acuminate, with .small, r/mote teeth, pale green and 

 shining. Flowers white, rarely reddi.sh, minute, in terminal racemes. Jl. 



SuBORDKR,— U A li O RAGE JE. 



Plants small, aquatic. Flowers minute, axillary, .sessile. Calyx entire, or 

 3 — 4-lobed. Petals 3—4, often 0. Stamens 1—8, inserted with the petals into 

 the summit of the calyx. Ovary inferior, 1 — 4-celled. Fruit dry, indehiscent, 

 1 — ^1-cellcd. Seed pendulous, 1 in each cell. 



8. PROSERPINACA. 



Lat. Proserpina, a Roman goddess ; from some fancied resemblance. 



Calyx tube adherent to the ovary, 3-sided, limb 3-parted ; petals 

 ; stamens 3 : stigmas 3 ; fruit 3-angled, 3-celled, bony, crowned 

 with the permanent calyx. — % Aqualic. Lvs. alternate. 



1. P. PALUsTRis. Spcar-kavcd Mcrmaid-wced. 



Lvs. linear-lanceolate, sharply serrate above the water, those below (if 

 anv) pinnatifid.— Ditches, swamps and ponds, often partly submersed, N. Eng. ! 

 to Ark. Root creeping. Stems ascending at base, 6 — 20' high, striate, round- 

 ish. Leaves 10—15" by 2 — 3", acute at each end, lower ones on short petioles, 

 and if growing in water, pinnatifid with linear segments. Flowers greenish, 

 sessile, 1 — 3 together in the axils of the upper leaves, succeeded by a very hard, 

 triangular nut. Jn. Jl. 



2. P. PECTiNACEA. Lam. (P. palustris, /?. Mr.) Cut-leaved Mermaid-ioeed. 

 Lvs. all pectinate, with linear-subulate segments ; fr. obtusely 3-angled. 



—Sandy swamps, in Ms. ! (rare) S. to Flor. Stems 5 — 10' high, ascending at 

 base from long, creeping roots. Leaves all finely and regularly divided into 

 very narrow segments. Styles 0. Stigmas attenuate above. Fruit rather 

 smaller (less than 1 " diam.) than in P. palustris, rugose when mature. Jl. Aug. 



9. MYRIOPHYLLUM. Vaill. 



Gt. jivpiog, a mjTiad, cpvWov, a leaf; from the numerous divisions of the leaf. 



Flowers c? , or frequently $ : calyx 4-toothed in the $ and 9 , 4- 

 parted in the d^ ; petals 4, often inconspicuous or ; stamens 4 — 8 ; 

 stigmas 4, pubescent, sessile ; fruit of 4 nut-like carpels cohering by 

 their inner angles. — %■ Submersed., aquatic herbs. Submersed lvs. parted 

 into capillar^/ segments. Upper fis. usually d^, middle ones $, loicer. 9. 



1. M. SPICATUM. — Spiked Water- Milfoil. 



Lvs. in verticils of 3s, all pinnately parted into capillary segments ; fls. 

 in terminal, nearly naked spikes ; Jloral lvs. or bracts ovate, entire, shorter than 

 the flowers ; lowest ones subserrate and larger; pet. broadly ov^ate ; sta. 8; carpels 

 smooth. — N. Eng. to Ark., in deep water, the flowers only rising above the sur- 

 face. Stems slender, branched, very long. Leaves composed of innumerable, 

 hair-like segments, always submerged. Flowers greeni.sh, sessile. Jl. Aug. 



2. M. VERTiciLLATL-M. WaMr-MUfoH. 



Lvs. in verticils of 3s, lower ones pinnately parted into opposite, capillary 

 or setaceous segments : /s. in terminal, leafy spikes ; Jloral lvs. pectinate-pin- 

 natifid, much longer than the flowers ; pet. oblong-obovate ; sta. 8 ; carpels 

 smooth.— In stagnant water, Can. to Flor. W. to Oregon. Stem long, less slen- 

 der than in the last, only the upper part emerging. Flowers small, green, ax- 

 illary, with conspicuous floral leaves. Sepals acute. Anthers oblong. Jl. Aug. 



3. M. HETEROPHYLLUM. Mickx. (Potamogctou verticillatum. Walt.^ 

 Lvs. in verticils of 5s, the lower ones pinnately parted into capillary 



lobes; .';;«7.t5 terminal, nearly naked; Jloral lvs. ovate-lanceolate, serrate, longer 

 than the flowers, crowded; pet. oblong; .'^fa. 4 — 6; carpels scabrous, with 2 slight 

 ridges on the back. — In sluggish Avater. Can. to Flor. and Tex., rare. Stem 

 23* 



