MYRIOPHYLLUM. LV. ONAGRACE^E. 267 



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, | 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 AL.ORAGEJB. 



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

 b 4-lobcd. 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, indehisent, 

 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 > pet* Is 

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

 with the permanent calyx. ^ Aquatic. Lvs. alternate. 



1. P. PALUSTRIS. Spear-leaved Mermaid-weed. 



Las. linear-lanceolate, sharply serrate above the water, those below (<i 

 any) pinnatifid. Ditches, swamps and ponds, oiten partly submersed, N. En^J 

 to Ark. Root creeping. Steins ascending at base, 6 20' high, striate, roun i- 

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

 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 harv\ 

 triangular nut. Jn. Jl. 



2. P. PECTINACEA. Lam. (P. palustris, /?. MX.} Cut-leaved Mermaid-wee*. 

 Lvs. all pectinate, with linear-subulate segments ; Jr. obtusely 3-angleo. 



Sandy swamps, in Ms. ! (rare) S. to Flor. Stems 510' high, ascending a^ 

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

 very narrow segments. Styles 0. Stigmas attenuate above. Fruit rathe-' 

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



9. MYRIOPHYLLUM. Vaill. 



Gr. pvptos, a myriad, ^vXAov, a leaf; from the numerous divisions of the leaf. 



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

 parted in the c? ; petals 4, often inconspicuous or ; stamens 4 8 ; 

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

 their inner angles. ^ Submersed, aquatic herbs. Submersed Ivs. parte& 

 into capilla.ry segments. Upper fls. usually c?, middle ones $, lower 9- 



1. M. SPICATUM. Spiked Water-Milfoil. 



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

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

 the flowers ; lowest ones subserrate and larger; pet. broadly ovate ; sta. 8; cur-pelt 

 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. VERTICILLATUM. Water- Milfoil. 



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

 or setaceous segments : fls. in terminal, leafy spikes ; floral Ivs. 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. Michx. (Potamogeton verticillatum. Walt.) 

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



lobes ; spikes terminal, nearly naked ; floral Ivs. ovate-lanceolate, serrate, longer 

 than the flowers, crowded ; pet. oblong ; sta. 4 6 ; carpels scabrous, with 2 slight 

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

 23* 



