6 Family Key 
G. Leaves either with distinct dilated stipular sheath or with axillary stipules; 
flowers greenish, 4 to many in an umbel-like or spike-like cluster. 
NAIADACEAE (p. 31) 
GG. Leaves with neither dilated sheath nor axillary stipules. 
H. Leaves equitant; flowers 10 or more in a head, monoicous, greenish 
or whitish. SPARGANIACEAE (p. 30) 
HH. Leaves not equitant; flowers 1—2 in a cluster, perfect, bright- 
yellow. PONTEDERIACEAE (p. 90) 
EE. Plants not submerged nor floating, at least rising out of the water if growing 
in it. 
I. Flowers surrounded by chaffy bracts or bristles or fine hairs, and no other 
perianth present, or no perianth at all. 
J. Cat-tails; perianth of many fine hairs; flowers in a cylindric spike-like 
cluster 10 cm. or more long and 2—2.5 cm. in diameter. 
TYPHACEAE (p. 30) 
JJ. Not cat-tails; perianth none, or of chaffy bracts, or of stiff usually serrate 
bristles, or of fine hairs (Eriophorum) ; flowers either not in spikes or the 
spikes smaller. 
K.  Perianth of |—3 chaffy bracts, or of hairs or bristles, or none at all; 
ovary |-celled, -l-seeded; stems hollow or not so; flowers often in spike- 
lets. 
L. Flowers monoicous, each subtended by 3 chaffy bracts; fruits ag- 
gregated into spherical bur-like heads; growing along borders of ponds 
in mud or shallow water. SPARGANIACEAE (p. 30) 
LL. Flowers mostly perfect, each subtended by 1—2 chaffy bracts; 
fruits rarely aggregated into spherical bur-like heads; often growing on 
dry land. 
M. Leaves 2-ranked; margins of leaf sheath not united; stem hol- 
low in nearly all species; fruit a grain. GRAMINACEAE (p. 36) 
‘MM. Leaves 3-ranked; margins of leaf sheath united; stem solid; 
fruit an akene. CYPERACEAE (p. 74) 
KK. Perianth of 6 similar chaffy bracts; ovary either 3-celled or 1-celled 
with 3 parietal placentae, 3 to many seeded; stem not hollow; flowers 
not in spikelets. JUNCACEAE (p. 90) 
II. Flowers with green or colored perianth which is not chaff nor hair-like nor 
bristle-like. 
N. Leaves without petiole, sheathing at base; sheath dilated and projecting 
as stipular points where it joins the blade; ovary superior; perianth small, 
green, not flower-like. JUNCAGINACEAE (p. 34) 
NN. Leaves often petioled, sometimes sheathing at base but in such case the 
sheath not projecting as stipular points where it joins the blade; ovary supe- 
rior or inferior; perianth often conspicuous and colored, flower-like even 
when greenish, 
©. Ovary superior; flowers regular. 
See MELANTHACEAE, LILIACEAE and CONVALLARIACEAE (p. 94) 
OO. Ovary inferior; flowers regular or irregular, 
P. Leaves equitant; flowers regular; stamens and style not coherent; 
anthers 3. IRIDACEAE (p. 110) 
PP. Leaves not equitant; flowers irregular; stamens and style coherent; 
anthers |—2. . ORCHIDACEAE (p. 112) 
