146 PONTEDERIACEAE 



1. HETERANTHERA R. & P. Mud-plantain. 



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Creeping or floating water plants. Leaves long-petioled, with broad, ovate, 

 cordate, rounded, or reniform blades, sometimes reduced to phyllodes. Flowers 

 perfect, solitary or few", subtended by a spathe-like bract. Perianth white or 

 blue, wath a slender tube. Stamens 3; anthers introrse, that of the anterior 

 stamen sagittate, those of the other two ovate. Ovary incompletely S-celled; 

 ovules numerous in two rows on each placenta. 



1. H. limosa (Sw.) Willd, Stem floating, 1-5 dm. long, branched; leaves 

 petioled; petioles 3-20 cm. long; blades ovate to oblong-ovate, 1-3 cm. long, 

 rounded or subcordate at the base; spathe 1-flowered; perianth blue or white; 

 tube 1.5-2 cm. long; lobes linear. Shallow water: Va. — Fla. — Mex. — Colo. — 

 S.D.; W. Ind. and Trop, Am. Plain. Je-Au. 



2. ZOSTERELLA Small. Water Star-grass. 



Submersed grass-like plants. Leaves sessile, narrowly linear, translucent. 

 Flowers perfect, 1 or 2, subtended by a bract. Perianth yellow, with a slender 

 tube. Stamens 3; anthers all sagittate, introrse. Ovary 1-celled with 3 parietal 

 placentae; ovules numerous, 2-ranked. [Schollera Schreb.] 



1. Z. dubia (Jacq.) Small, Stem floating or creeping, 2-10 dm. long, 

 branched; leaves linear, flat, sheathing at the base, 1-2 dm. long; perianth-tube 

 1 mm. thick; lobes hnear, 8-12 mm. long. Heteranthera graminea (Michx.) 

 Vahl. H. dubia (Jacq.) MacM. Still water: Ont.— Fla. — Mex.— Ore.; W. Ind. 

 Plain, My-S. 



Family 18. MELANTHACEAE. Bunch-flower Family. 



Leafy-stemmed perennials, with rootstocks or solid bulbs. Flow^ers race- 

 naose or paniculate, perfect, dioecious, or polygamous. Petals and sepals 

 each 3, distinct or nearly so. Stamens 6; filaments often partly adnate to 

 the base of the sepals and petals; anthers versatile. Pistil of 3 united car- 

 pels; ovary 3-celled; styles 3. Fruit a septicidal capsule. 



Plants with rootstocks (except in ISTo. 3); petals and sepals glandless. 

 Anthers oblong or ovate, 2-celled. 



Anthers intftirse; flowers involucrate with .3 bractlets. 1. Tofieldia.. 



Anthers extrorse; flowers not involucrate. 2. XEROPHTLLUiL 



Anthers cordate or reniform, confluently 1-celled. 



Flowers racemose, perfect, nodding; plants glabrous, with narrow leaves. 



3. Stexanthella. 



Flowers paniculate, polygamous; more or less pubescent plants, with broad 

 plaited leaves. 4. VeratrUM. 



Plants with bulbs; petals and sepals with a more or less distinct gland. 



Ovary partly inferior; gland obcordate. 5. Anticlea. 



Ovary wholly superior; gland obovate or semiorbicular, 6. Toxicoscordton. 



1. TOFIELDIA Huds. Scottish Asphodel. 



Perennial herbs, with short rootstocks, fibrous roots, 2-ranked linear equitant 

 leaves, and small flowers in a terminal raceme. Flowers involucrate by 3, more or 

 less united bractlets below the calyx. Petals and sepals oblong or obovate, sub- 

 equal, persistent, glandless. Stamens 6; anthers ovate, introrse. Capsule 

 septicidal to the base, many-seeded. 



Stem glabrous, scapiform; seed unappendaged. 



Stem leafy at the base only; flowers short-pedicelled, 1. T, palustris. 



Stem with a leaf also at or above the middle; flowers sessile. 2. T. coccinea. 

 Stem viscid-pubescent, at least above: seeds appendaged. 



Bractlets broadly triangular, connate two-third? their length. 3. T. intermedia. 



Bractlets lanceolate-triangular, connate half their length or less. 4. T. occidentalism 



1. T, palustris Huds. A glabrous plant, with a scape-like, leafless stem* 

 3-15 cm. high, and a few basal leaves, 2-10 cm. long; raceme in flower short, oblong? 

 dense; flowers greenish; petals and sepals obovate, obtuse; capsule oblong- 

 globose, minutely beaked. In wet places ; Greenl.— Que. — Minn. — B.C. ; Alaska; 

 Eu. Alp, — Suhalp, Je-Jl. 



