PONTEDERIACEAE 243 
10. Commelina élegans H.B.K. Stems erect or branching at the base ; branches de- 
cumbent, rooting at the nodes, 2-8 dm. long, with short or elongated puberulent internodes : 
leaf-blades lanceolate to elliptic or oblong-lanceolate, 4-10 cm. long, acute or acuminate, 
some often rounded at the base ; sheaths 1-1.5 cm. long, naked or sparingly ciliate on the 
spreading margin : spathes short-peduncled, glabrous, at least without long hairs at the base, 
1.5-2 em. long, acute: petals blue or white: capsules obovoid, 4 mm. long, reticulated 
especially on the dorsal lobe : seeds 3, smooth. 
In sand, peninsular Florida and tropical America. Spring and fall. 
11. Commelina hirtélla Vahl. Stems erect, ascending or reclining, 2-12 dm. tall, 
somewhat pubescent, more or less branched: leaf-blades lanceolate or oblong-lanceolate, 
10-20 em. long, acuminate, often roughish, narrowed into short petiole-like bases ; sheaths 
1-2.5 em. long, fringed with brown hairs : peduncles very short : spathes usually clustered, 
triangular or triangular-ovate, 2-2.5 cm. long, acute, united at the base, strongly nerved 
and cross-nerved : capsules 7-8 mm. long, smooth and shining: seeds 5 in each capsule, 
4—6 mm. long, granular-puberulent. 
In swamps and alluvial soil, New Jersey to Missouri, Florida and Texas. Summer and fall. 
FAMILY 5. PONTEDERIACEAE Dumort. PICKEREL-WEED FAMILY. 
Bog or aquatic herbs, with rootstocks. Leaves alternate, often clustered, 
sometimes mainly basal: blades ribbon-like or much dilated. Flowers perfect, 
more or less irregular, solitary or in spikes subtended by leaf-like spathes. Peri- 
anth corolla-like: members 6, partially united. Androecium of 3-6 stamens 
partially adnate to the perianth. Filaments filiform, or dilated at the base, or 
thickened about the middle. Gynoecium a compound pistil. Ovary 3-celled 
with axile placentae, or 1-celled by suppression. Stigma entire or minutely 
toothed. Ovules solitary or numerous, anatropous. Fruit a 1-celled 1-seeded 
utricle, or a many-seeded capsule. Endosperm mealy, copious, surrounding the 
central embryo. 
Stamens 8, or rarely 1-4. 1. HETERANTHERA. 
Stamens 6. 
Ovary 1-celled (by suppression): ovule and seed solitary : fruit indehiscent. 2. PONTEDERIA. 
Ovary 3-celled : ovules and seeds numerous: fruit 3-valved. 3. PIAROPUS. 
1. HETERANTHERA R. & P. 
Herbs, with creeping or floating stems. Leaves alternate: blades broadened, or 
grass-like, often petioled, sometimes reduced to phyllodes. Spathes bract-like, 1-several- 
flowered. Perianth white, blue or yellow: members equal or nearly so, narrow, or 
dilated. Stamens 3, or rarely 1-4: filaments often unequal: anthers erect, introrse. 
Ovary 3-celled, sometimes incompletely so: style filiform. Ovules numerous, in 2 
rows on each placenta. Capsule somewhat elongated, enclosed in the withered perianth. 
Seeds numerous, ribbed. [Schollera Schreb. ] 
Leaves not differentiated into blade and petiole, linear: perianth yellow. 1. H. dubia. 
Leaves differentiated into petiole and blade: perianth white or blue. i 
Leaf-blades longer than broad : spathes 1-flowered. 2, H.limosa. . 
Leaf-blades broader than long: spathes 2-5-flowered. 3. H. reniformis. 
1. Heteranthera dübia (Jacq.) MacM. Stems floating or creeping, 2-9 dm. long, 
branched : leaves linear, more or less elongated, flat, acute, sheathing at the base: spadix 
1-2-flowered : perianth light yellow, delicate ; tube about 1 mm. thick ; lobes linear, 8-12 
mm. long: filaments dilated below: anthers linear-sagittate: seeds oblong or oval-ob- 
long, 1.5 mm. long, delicately ribbed. [H. graminea (Michx.) Vahl.] 
In still water, Ontario to Oregon, Florida and Mexico. Summer and fall. WATER STAR-GRASS. 
2. Heteranthera limósa (Sw.) Willd. Stems 1-5 dm. long, branched, succulent : 
leaves often numerous ; petioles terete or nearly so, 3-20 cm. long ; blades ovate to oblong- 
ovate, 1-3 cm. long, obtuse, entire, rounded or subcordate at the base: phyllodessometimes 
present: spathe 1-flowered : perianth white or blue; tube slender, 1.5-2 cm. long; lobes 
linear, shorter than the tube: seeds delicately ribbed. 
_ In shallow water or muddy places, Virginia to Missouri, Florida, Louisiana and tropical America. 
Spring to fall. Mup PLANTAIN. 
3. Heteranthera renifórmis R. & P. Stems creeping in the mud, 0.5-4 dm. long, 
or more elongated : leaves few ; petioles 0.5-2 dm. long; blades reniform to orbicular- 
reniform, 3-6 cm. broad, entire, more or less deeply cordate: spathe 2-5-flowered : 
