Naiadaceae 33 
II. Leaves perfoliate or somewhat clasping at base; spike 3 cm. or less long. 
J. Leaf-tip cucullate; leaves lanceolate or lanceolate-oblong. W. 
P. praelongus Wolfg. (White-stem Pond-weed) 
JJ. Leaf-tip not cucullate; leaves orbicular or ovate or ovate-lanceolate. W. C. 
E. (P. perfoliatus richardsonii. ) 
P. perfoliatus Lb. (Clasping Pond-weed) 
HH. Leaves all linear. 
K. Stipules adnate to the leaf-bases. 
L. Leaves not capillary, 2.5—4 mm. wide, margin minutely serrulate thruout; 
free part of stipule longer than sheath. W. E. 
P, robbinsii Oakes 
LL. Leaves capillary, 0.1—0.3 mm. wide, margin entire; free part of stipule 
shorter than sheath. W. E. 
P. pectinatus L. (Fennel-leaved Pond-weed ) 
KK. Stipules free from the leaf-bases, axillary. 
M. Leaves linear, 2—4 mm. wide, 5—20 cm. long, without glands at base; 
stipules |—3.5 cm. long; plants mostly with propagating buds. W. (P. 
compressus. ) P. zosterifolius Schum. 
MM. Leaves linear or capillary, 0.1—1.5 mm. wide, 2—12 cm. long, with 
2 small glands at base; stipules 0.5—-1.5 cm. long; plants with propagating 
buds. W. E. P. pusillus L. (Small Pond-weed) 
MMM. Leaves linear, 0.4——2 mm. wide, |.5—8 cm. long, without glands at 
base; stipules 1.3—2.4 cm. long; plants nearly always without propagating 
buds. E. (P. californicus; P. foliosus californicus. ) 
P, foliosus Raf. 
ZOSTERA EEL-GRASS 
Stem much branched. Leaves in 2 rows, flat, 4—13 dm. long (ours), somewhat 
like those of the cat-tail. Flowers perfect, monoicous (ours). Style long. Mature fruit 
a cylindric or flask-shaped utricle, rounded at base. On muddy bottom, in quiet tide- 
water, submerged. (Gk. zoster—a belt; referring to the leaves.) W. 
Z. marina L. (Hel-grass) 
PHYLLOSPADIX SEA BASKET-GRASS 
Stem slender. Leaves grass-like. Flowers dioicous, each covered by hyaline en- 
velope. Style short. Mature fruit coriaceous, indehiscent, deeply cordate-sagittate at 
base. Seeds membranous, globose. On rocky shores subjected to strong tidal currents, 
about the low-tide line. (Gk. phyllon—tleaf, +-spadix; inflorescence enclosed in leaf- 
base. ) 
A. Leaves flat, 2—4 mm. or more wide; peduncles basal, simple, solitary or in 2’s, |—-5 
cm. long. W. P. scouleri Hook. 4 
AA. Leaves complicate, 0.7—1.5 mm. or less wide; peduncles cauline, mostly branched, 
in 2’s or 3’s, mostly 3—14 cm. long. W. 
P. torreyi Wats. 
NAIAS WATER-NYMPH 
Submerged marine or freshs-water herbs; roots fibrous; stems slender, branching, 
unarmed or spiny. Leaves alternate or opposite or whorled; blade linear, spiny on 
margin or back or both, acute or obtuse, sometimes tipped with one or more subulate 
spines, sheathing at base; leaf-sheath rounded or auriculate, entire or spinulose-toothed. 
Flowers monoicous or dicicous, solitary in the axils. Perianth-like envelope of the stam- 
