Myriophyllum. LV. ONAGRACEJE. 367 



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

 Eng., Brit. Am. W. to Or. Stem diaphanous, juicy, 5—10' high. Leaves 1 — 

 2' long, i as wide, acute or acuminate, with small, r«mote teeth, pale green and 

 shining. Flowers white, rarely reddish, minute, in terminal racemes. Jl, 



Suborder,— H ALORAGE-E. 



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— 4rcelled. Fruit dry, indehiscent, 

 1 — 4-celled. 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 

 Vsith the permanent calyx. — %■ Aquatic. Lvs. alternate. 



1. P. PALUSTRis. Spear-leaved Mcrmaid-iceed. 



lA-5. linear-lanceolate, sharply serrate above the water, those below (il 

 any") pinnatifid.— Ditches, swamps and ponds, often partly submersed, N.Eng. I 

 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, 0. Mx.) Cut-leaved Mermaid-weed. 

 Jjvs. 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. paltfctris, rugose when mature. Jl. Aug. 



9. MYRIOPHYLLUM. Vaill. 



Gr. fivptos, a myriad, ^uXXov, a leaf; from the numerous divisions of the leaf. 



Flowers (?, or frequently 5; calyx 4-toothed in the 5 and 9, 4- 

 parted in the cf ; 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 capillary segments. Upper Jls. usually c?, middle ones $, lower 9- 



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



Lvs. iiL vsrticils of 3s, all pinnately parted into capillary segments ; fis. 

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

 the flowers ; lomest o7ies subserrate and larger; pet. broadly ovate ; sta. S; carpels 

 imooth.— 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 greenish, sessile. Jl. Aug. 



2. M. VERTiciLLATCM. Water- Mllf Oil. . 



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

 or setaceous segments : fls. in terminal, leafy spikes ; floral lvs. pectinate-pm- 

 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. 3Iichx. (Potamogctou verticillatum. Walt.) 

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



lobes ; spikes terminal, nearly naked ; floral lvs. ovate-lanceolate, ^^^''^.^J^' ^^'^^f^ 

 than the flowers, crowded ; pel. oblong ; sta. 4—6 ; carpels scabrous, with 2 sUght 

 ridges on the back.— In sluggish water. Can. to Flor. and Tex., rare, btem 

 23* 



