146 
XXIX. HALOEAGACEJE. 
[Hippuris. 
Woods and coppices in shady situations, common, If. — 8. — 
Rhizome creeping. Stem 1 — l-' f ft. high. Leaves scarcely cordate at the 
base, upper ones narrow-ovate. — The only certain character between 
this and the next is afforded by the structure of the ovary, as first 
pointed out by Dr. Wight ; that giving it the difference of external 
form : but even this is diminished in value by the 2-lobed stigma, 
indicating a tendency to produce the second ceil also, in the ovary of 
C. alpina. The nectary which surrounds the base of the filament is 
a little more prominent than in the following species. 
2. C. alpina L. (alpine E.) ; stem ascending nearly glabrous, 
leaves cordate toothed shining as long as the fiat petiole, pe- 
dicels subtended by minute setaceous bracts, calyx more or less 
glabrous, ovary 1 -celled at length inversely oblong. E. B. 
t, 1057. 
Woods, coppices, and stony places, especially by the sides of lakes 
in the north of England and Scotland. If. 7, 8 This is very 
near to the preceding ; but is usually much smaller and with a nar- 
rower ovary and fruit. The petioles appear flat in consequence of the 
leaf being usually decurrent along it, constituting, as it were, mem- 
branaceous wings. Mature fruit, which is abundant on C. Lu- 
tetiana, we have seldom observed on this plant. What is called C. 
intermedia sometimes belongs to the present species, sometimes to the 
last. 
Ord. XXIX. HALORAGACE2E R. Brown. 
Calyx-tube adnate with the ovary ; limb of fertile flowers 
minute, 3 — 4-partite or wanting. Petals present or wanting. 
Stamens equal in number to the lobes of the calyx, or double 
as many, rarely fewer. Ovary with 1 — 4 cells; ovules solitary 
pendulous. Stigmas as many as there are cells, papillose or 
penicilliform. Fruit dry, indehiscent, 1 — 4-celled, or composed 
of 4 indehiscent carpels slightly cohering by their inner angles 
and eventually separating. Seeds solitary, pendulous. Albumen 
fleshy, sometimes very thin. Embryo straight. Radicle su- 
perior. — Mostly Herbs (the British ones especially ), aquatics. 
Leaves various as to insertion. The stamens and pistils often 
separated ; the former are then inserted with the petals into the 
base of the calyx. 
1. Hippuris. Stam 1. Stigma 1. Fruit 1-seeded. 
2. Myriophyllum. Monoecious. Stam. 4 — 8. Stigmas 4. Fruit 4- 
seeded. 
1. Hippuris Linn. Mare’s Tail. 
Perianth single, superior, forming a very indistinct rim to the 
germen. Stam. 1. Style 1. Fruit 1-celled, 1-seeded. — Named 
from ir~or, a horse, and ovpa, a tail. 
