162 Ceratophyllaceae 
many, many-ovuled, united; stigma disk-like, 8—24 radiate. Fruit ovoid, naked. (%he 
white ones were dedicated by the Greeks to the water nymphs.) W. C. E.: (N. ad- 
vena for our region.) N. polysepala Gr. 
CERATOPHYLLACEAE Hornwort Family 
Herbs, perennial, aquatic, submerged; stems slender, widely branching. Leaves 
whorled, in ours thread-like or stag-horn-like. Flowers monoicous or dioicous, sessile, 
solitary in the axils. Perianth many-parted; segments entire or toothed. Stamens nu- 
merous; anthers extrorse, the connective prolonged into a thick appendage beyond the 
sacs. Ovary superior, I-celled, 1-ovuled. 
CERATOPHYLLUM HORNWORT 
Stem densely leafy at least above (ours). Terminal tuft of leaves slimy and 
persisting thru the winter. Leaves spinulose-serrate or smooth, forked. Sterile flowers 
with 10—20 stamens. Fruit beaked with the long persistent style. (Gk. keras=a 
horn, phyllon—a leaf; the leaves branch stag-horn-like.) W. E. 
C. demersum L. 
RANUNCULACEAE Buttercup Family 
Herbs or shrubs, annual or perennial, climbing when shrubby (ours), glabrous or 
pubescent with simple hairs; juice acrid. Leaves alternate or opposite (Clematis) or 
the stem with a single whorl (Anemone), simple or compound; stipules none, but the 
base of the petiole often clasping or sheathing. Flowers regular or irregular. Sepals 
3—15, often petal-like, imbricated (except in Clematis). Petals of about the same 
number as the sepals, rarely more, rarely none. Stamens 10—many, hypogynous. Car- 
pels |—many, 1|-celled; ovules |—many. In fruit the carpels becoming akenes or 
follicles or berries. 
A. Leaves either alternate or all basal. 
B. Flowers spurless or |-spurred; leaves various. 
C. Flowers regular; leaves various. 
D. Leaves simple. 
FE. Leaves entire; fruit of 1-seeded akenes. Myosurus (p. 168) 
EE. Leaves either not entire, or else fruit of several-seeded follicles. 
F. Petals none. 
G. Leaves entire or crenate: sepals 5-15; fruit of follicles: follicles 
several-seeded, not 4-angled. CALTHA (p. 163) 
GG. Leaves palmately lobed; sepals 4; fruit of akenes; akenes 1|- 
seeded, 4-angled. TRAUTVETTERIA (p. 168) 
FF. Petals present. 
H. Plants glabrous; petals 15—-25; fruit of many-seeded follicles. 
TROLLIUS (p. 164) 
HH. Plants either pubescent or petals fewer; fruit of 1-seeded akenes. 
I. Flowers white; stems submerged; leaves filiform when submerged ; 
akenes transversely rugose; petals with a naked spot or pit at 
base. BATRACHIUM (p. .169) 
II. Flowers yellow; stems mostly not submerged; rarely the leaves 
filiform; akenes not transversely rugose; petals with a small scale 
at the base of the claw. RANUNCULUS (p. 169) 
DD. Leaves compound. 

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