73. CEKATOPHYLLACE.E. — 74. CALLITRICHACE.E. 371 
Order I,XXIII CERATOPH VI.LACE^. 
I Fl. monoecious. Perianth free, in many divisions. Antli. 12 
I — 20, sessile, 2-celled, 2-pointed ; cells again partially divided. — 
I Perianth usually wanting. Ovary 1 -celled. Seed 1, pendulous. 
-Embryo straight ; cotyledons 4, alternately smaller. — No sti- 
pules. — ( )nly one genus. 
1. Cekatophyl'lum Linn. Horn wort. 
1. C demer'siim (L.) ; segments of I. /inear-tiliform, fr. wing- 
It .s.s having a spine on each side near the base and tipped with 
t!ie curved subulate style. — E. B. 947.— L. 2 — 4 times forked, 
dark green, segments of uppermost 1. broader and more rigid. 
Sometimes the spines are wanting, the style is short, and the 
surface rough with minute tubercles. — Ponds and ditches, I'are. 
P. Yl. VII. E. S. I. 
C . suhiiier' sum (L.) : segments of I. setaceous, fr. destitute 
of spines covered when ripe with cylindrical tubercles and tipped 
\\ ith the short curved style. — E. B. 679. — L.pale iireen. Young 
fl . smooth.— Ponds and ditches. P. VI. VII. " E. 
Order LXXIV. C.ALLlTIUCHACEi*:. 
Fl. mostly monoecious, solitary, minute, usually with 2 white 
bracts, no perianth. Stam. 1. Filament long. Anth. reniform, 
l-celled,openingtransversely at the top. — Perianth none. Ovary 
1, 4-angled, 4-celled. Styles 2, subulate. Fr. dry, 4-celled, 4*- 
lobed ; separating into 4 1-seeded indehiscent carpels. Embryo 
in axis of fleshy albumen. Kadicle superior, long. Cotyledons 
short, terete. — No stipules. — Only one genus of aquatic plants. 
1. Callit'riche Zm". Water-Starwort. 
A. Tj. mirrou'ed at the hase ; lower linear, submerged : upper 
floating, broad, often spathulate and forming a rosette. Fr. 
of 4 lobes cohering in pairs. — C. verna L. 
1. C. 'pal us'tris (L. em. Piend. & Br.) ; fr. nearly sessile longer 
than broad, lobes parallel bluntly keeled on the back convex on the 
sides, styles erect deciduous, bracts straightish deciduous. — C. 
wr^«rt (L. em. Kiitz.). C . vernalis (Koch). E.B.m. 7?. v. 129. 
— Floating 1. ovate-spathulate, in a rosette, rarely wanting. 
Fr. small : keels of each pair of lobes converging. — Ponds and 
slow streams. A. or P. IV. — IX. E. S. I. 
