Flowers produced from a cleft in the margin of the frond, usually three together surrounded by a spathe; two of them staminate, consisting of a stamen only; the other pistillate, of a simple pistil; the whole therefore imitating a single diandrous flower. _Ster. Fl._ Filament slender; anther 2-celled, didymous; the cells dehiscent transversely; pollen-grains large, spherical, muricate. _Fert. Fl._ Ovary 1-celled; style and truncate or funnel-shaped stigma simple. Ovules and seeds 1--7.--Fronds 1--5-nerved, producing a single rootlet beneath (which is dest.i.tute of vascular tissue), proliferous from a cleft in the margin toward the base, and at length stipitate; the tissue abounding with bundles of rhaphides. (An old Greek name of uncertain meaning.)

[*] _Ovule solitary, orthotropous or nearly so; frond 1--3-nerved, thin._

[+] _Fronds oblong, stalked at base, remaining connected._

1. L. trisulca, L. Fronds oblong to oblong-lanceolate (6--9" long), attenuate at base into a slender stalk, denticulate at the tip, very obscurely 3-nerved, often without rootlets, usually several series of offshoots remaining connected; spathe sac-like; seeds ovate, amphitropous, with small round operculum.--Ponds and springy places, N. Scotia to N. J., west to the Pacific. (Eu.)

[+][+] _Fronds oblong to elliptical or round-ovate, sessile, soon separating._

2. L. Valdiviana, Philippi. _Fronds elliptic-oblong_, small (about 1"

long), rather thick, usually somewhat falcate, _obscurely 1-nerved; spathe broad-reniform_; utricle long-ovate, pointed by the long style; _seed orthotropous_, oblong, _with a prominent acute operculum_. (L.

Torreyi, _Austin._)--Pools, N. J. and southward, westward across the continent. (S. Am.)

3. L. perpusilla, Torr. _Fronds obovate or roundish-obovate_, oblique (1--1" long), _obscurely 3-nerved_; utricle ovate; style rather long; _seed orthotropous_, ovate or oval, obtuse, _with scarcely apiculate operculum_.--N. Y. and N. J., west to Mich. and Wisc.--Var. TRINeRVIS, Austin, has larger, distinctly 3-nerved fronds, and an unequally cordate seed.

4. L. mnor, L. _Fronds round- to elliptic-obovate_ (1--2" in diameter), rather thick, _very obscurely 3-nerved; spathe sac-like_; utricle short-urn-shaped, tipped with a short style; seed oblong-obovate, _amphitropous, with prominent rounded operculum_.--Stagnant waters, throughout N. Am. (Eu.)

[*][*] _Ovules 2--7, anatropous; fronds very thick and spongy, flat above, very obscurely 5-nerved (1--3" long)._

5. L. gibba, L. Fronds obovate-elliptic to nearly orbicular, almost hemispherical, soon separating; bract sac-like.--Mo. (?) to Ariz. and Calif.

3. WoLFFIA, Horkel.

Flowers central, bursting through the upper surface of the globular (or in some foreign ones flat) and loosely cellular frond, only 2; one consisting of a single stamen with a 1-celled 2-valved anther; the other of a globular ovary, tipped with a very short style and a depressed stigma. Ovule orthotropous, rather oblique in the cell. Utricle spherical. Alb.u.men thin.--Fronds rootless, proliferous from a cleft or funnel-shaped opening at the base, the offspring soon detached; no rhaphides.--The simplest and smallest of flowering plants, from --{2/3}" long (an African and Cuban species much larger), floating as little grains on the water. (Named for _John Fred. Wolff_, who wrote on Lemna in 1801.)

1. W. Columbiana, Karsten. Globose or globular, {1/3}--{2/3}" long, very loosely cellular, light green all over, not dotted; stomata 1--6; the opening at the base circular and with a thin border.--Floating rather beneath the surface of stagnant waters, Conn. to N. J., west to Minn. and La.

2. W. Brasiliensis, Weddell. Oblong, smaller and more densely cellular, flattish and deep green with many stomata above, tumid and pale below, brown-dotted all over, anterior edge sharp, opening at base circular.--Growing with the last, but floating on the surface.

ORDER 125. ALISMaCEae. (WATER-PLANTAIN FAMILY.)

_Marsh herbs, with scape-like stems, sheathing leaves, and perfect or moncious or dicious flowers; perianth of 3 herbaceous persistent sepals and as many (often conspicuous) white deciduous petals, which are imbricate or involute in bud; stamens 6 or more, included; ovaries numerous, distinct, 1-celled and mostly 1-ovuled, becoming achenes in fruit_ (in our genera); _seeds erect; campylotropous._--Roots fibrous; leaves radical, petiolate and strongly nerved with transverse veinlets, the earlier sometimes without blade; flowers long-pedicellate, mostly verticillate, in a loose raceme or panicle, with lanceolate scarious bracts slightly connate at base.

1. Alisma. Flowers perfect, usually 6-androus. Carpels flattened, in one whorl.

2. Sagittaria. Flowers mostly unis.e.xual. Stamens rarely few. Carpels flattened, in dense heads, winged.

3. Echinodorus. Flowers perfect. Stamens 6 or more. Carpels capitate, turgid and ribbed, often beaked.

1. ALiSMA, L. WATER-PLANTAIN.

Flowers perfect. Petals involute in the bud. Stamens definite, mostly 6.

Ovaries many in a simple circle on a flattened receptacle, forming flattened coriaceous achenes, which are dilated and 2--3-keeled on the back.--Roots fibrous. Leaves all from the root, several-ribbed, with connected veinlets. Scape with whorled panicled branches. Flowers small, white or pale rose-color. (The Greek name; of uncertain derivation.)

1. A. Plantago, L. Perennial by a stout proliferous corm; leaves long-petioled, ovate, oblong, or lanceolate or even linear, acute, mostly rounded or heart shaped at base, 3--9-nerved; panicle loose, compound, many-flowered (1--2 long); carpels obliquely obovate, forming an obtusely triangular whorl in fruit.--Shallow water and ditches, across the continent. Very variable as to foliage, but the leaves usually more broadly cordate-ovate than in Old World forms (var.

Americanum, _R. & S._); when growing under water thinner and narrowly lanceolate. (Eu., etc.)

2. SAGITTaRIA, L. ARROW-HEAD.

Flowers moncious, or often dicious in n. 1 and 4, and polygamous in n. 7. Petals imbricated in the bud. Stamens indefinite, rarely few.

Ovaries many, crowded in a spherical or somewhat triangular depressed head on a globular receptacle, in fruit forming flat membranaceous winged achenes.--Marsh or aquatic, mostly perennial, stoloniferous herbs, with milky juice and fibrous roots; the scapes sheathed at base by the bases of the long cellular petioles, of which the primary ones, and sometimes all, are flattened, nerved, and dest.i.tute of any proper blade (i.e. are phyllodia); when present the blade is arrow-shaped or lanceolate, nerved and with cross-veinlets as in Alisma. Flowers produced all summer, whorled in threes, with membranous bracts; the sterile above. (Name from _sagitta_, an arrow, from the prevalent form of the leaves.)

-- 1. SAGITTARIA proper. _Flowers moncious, with the lower whorls pistillate, or dicious; stamens few or numerous, covering the receptacle; sepals spreading or reflexed in fruit._

[*] _Filaments numerous, narrow, as long as or longer than the linear-oblong anthers; bracts 3, distinct; fruiting heads larger._

1. S. variabilis, Engelm. Scape (--4 high) angled, with one or more of the lower whorls fertile; leaves very various, almost always sagittate; bracts mostly pointed; pedicels of the fertile flowers at least half the length of the sterile ones; petals wholly white; filaments glabrous, nearly twice the length of the anthers; achenes obovate (about 1"

long), winged on both margins, with a long curved or usually horizontal beak --{1/3} its length. (S. sagittaefolia, _L._, var. variabilis, _M.

Micheli._)--In water or wet places, very common; exceedingly variable in size and foliage, ordinarily with narrow halberd-shaped or sagittate leaves,--sometimes dicious, with large, broad and obtuse leaves (var.

OBTuSA), or moncious, with large, broad and acute leaves (var.

LATIFLIA), or the narrow leaves with long and linear diverging lobes (var. ANGUSTIFLIA), or with some leaves lanceolate or ovate-lanceolate, others more or less sagittate (var. DIVERSIFLIA), etc. Root propagating by stolons tuberiferous at the extremity.--The European species has the fertile pedicels only {1/3} or the length of the sterile; claws of the petals purple-tinged; filaments not longer than the anthers; and achenes almost orbicular, very broadly winged and with a short straight beak.

Var. p.u.b.escens, Engelm. Upper part of petiole and scape and especially the orbicular-ovate obtuse bracts and sepals p.u.b.escent or woolly; beak of fruit horizontal.--N. J. and Penn. to Ga.

Var. (?) gracilis, Engelm. Lobes of the sagittate leaves very narrowly linear (--2" wide); achene narrowly cuneate-obovate (2" long), the beak long, stout, and strongly recurved, the sides usually strongly 1--3-crested. (S. cristata, _Engelm._?)--Ma.s.s. to western N. Y.; Iowa.

2. S. lanciflia, L. Scape 2--5 high, with several of the lower whorls fertile; leaves lanceolate or lance-oblong, rarely linear, all with a tapering base, thick or coriaceous (6--18' long and on a long and stout petiole, never sagittate), the nerves mostly arising from the very thick midrib; bracts ovate, acute or ac.u.minate; pedicels slender, the fertile scarcely shorter than the sterile ones; filaments p.u.b.escent; achenes falcate, winged on the back, pointed with an incurved beak.--Swamps, Md.

to Ky., Mo., and southward. (W. Ind.)

[*][*] _Filaments very short, with enlarged mostly glandular base; anthers ovate or short-oblong; fruiting heads small; bracts more or less connate; leaves very rarely sagittate._

3. S. heterophlla, Pursh. Scape weak (3'--2 high), at length proc.u.mbent; leaves lanceolate or lance-oval, entire, or with one or two narrow basal sagittate appendages; _bracts roundish, obtuse_; flowers of the lowest whorl fertile and _almost sessile_; the sterile on long pedicels; filaments glandular-p.u.b.escent; _achenes narrowly obovate with a long erect beak_.--N. Eng to Fla., west to Minn. and Mo. Varies as to foliage, the leaves being broad (var. ELLiPTICA, Engelm.), or rigid and narrowly lanceolate with stout petioles (var. RiGIDA, Engelm.), or nearly linear (var. ANGUSTIFLIA, Engelm.)

4. S. graminea, Michx. Scape 3'--2 high; _phyllodia flat_, mostly _broadly linear, ac.u.minate_; leaves ovate-lanceolate to linear, on long slender petioles, sometimes reduced to the petiole merely; bracts rather obtuse; whorls of flowers often few, all staminate or the lower fertile; _pedicels_ slender, _spreading_, nearly equal; _filaments 15--20, glandular-p.u.b.escent; achene small_ (" long), narrowly obovate, almost beakless, _winged on the back, flat and scarcely costate on the sides_.--N. Eng. to Minn., south to the Gulf; very variable.

5. S. teres, Watson. _Phyllodia terete, very acutely attenuate_ upward, 3--12' long, very rarely bearing a narrow blade; scape --1 high; bracts connate at base; _pedicels_ in 1--3 whorls, all very _slender and spreading_, 1 or 2 fruiting, --1' long; filaments 12, dilated, p.u.b.escent; _achene_ obovate, 1" _long, with an erect beak_, the margins and sides _crenately several-crested_.--In shallow water, S. New Eng. to N. J. (Hyannis, Ma.s.s., _Deane_; Wading River, L. I., _Miller_; barrens of N. J., _Torrey_.) Phyllodia usually very strongly nodose.

(Addendum)--Sagittaria teres has been collected also at Brewster, Ma.s.s.

(_Farlow_).

6. S. natans, Michx., var. lorata, Chapm. Usually dwarf; _leaves linear, strap-shaped, obtuse or acutish_, 1--6' long, equalling or shorter than the scape, very rarely with a narrow blade; pedicels in 1--3 whorls, only 1 or 2 fruiting, _stouter and recurved_; bracts connate or spathe-like; _filaments 6--8, glabrous; achene_ obovate, _short-beaked, 1" long_, the margins and sides _crenately crested_. (S. pusilla, _Pursh._)--In mud or shallow water, near the coast; N. Y. to Fla.

Var. (?) gracillima, Watson. Scape and the almost or wholly bladeless leaves very slender and greatly elongated (2--4 long, 1" wide); pedicels all elongated, in usually distant whorls, the lower pistillate, slender and spreading; fruit unknown. (S. natans, _Engelm._ in Torr.

Bull. ix. 4.)--In deep water of streams in E. Ma.s.s. (_Hitchings, Boott, C. E. Faxon_, etc.) Wholly submerged, only 1 or 2 flowers appearing at a time, floating on the surface. The fruit, maturing under water, has not yet been collected.

-- 2. LOPHIOCaRPUS. _Fertile flowers perfect; stamens 9--15, at the base of the receptacle; sepals erect and embracing the fruit._

7. S. calycna, Engelm. Scape weak (3--9' high), at length mostly proc.u.mbent; usually only the lowest whorl fertile, with pedicels as long as those of the sterile flowers, recurved in fruit; bracts...o...b..cular, obtuse or rarely pointed; filaments slightly rough, as long as the anthers; achenes obovate with a short horizontal style; leaves broadly halberd-shaped, obtuse or acutish, with wide spreading lobes, often wider than long, or lanceolate or sometimes reduced to linear phyllodia.--Maine to Del., west to Wisc., Mo., and Tex. Quite variable, several forms being enumerated, as var. SPONGISA, with spongy texture and bladeless submerged leaves, eastward; and westward, var. FLuITANS, with lance-linear floating leaves.

3. ECHINoDORUS, Richard.

Flowers perfect. Petals imbricated in the bud. Stamens 6--21 or more.

Ovaries several or many, imbricated in a head, forming thick and ribbed achenes in fruit, often beaked with a projecting persistent style.--Mostly annuals, with the habit of Sagittaria, the naked stems sparingly branched or simple, and the flowers on rather short pedicels, in whorls of 3--6 or more. Fl. summer and autumn. (Name from ?????d??, _p.r.i.c.kly_, or from ??????, and d???? _a leathern bottle_, applied to the ovary, which is in most species armed with the persistent style, so as to form a sort of p.r.i.c.kly head of fruit.)