174 THE MARESTAIL FAMILY. [Myriophyllum. 
Stamens4or8s. Stigmas and seeds 4. : ; : - . 1. MyriopHyLuumM. 
Stamen, stigmaandseed1 . : . . ° . . . 2. HipPpuRis. 
I. MYRIOPHYLLUM. MYRIOPHYLL. 
Aquatic plants, with finely pinnated, whorled leaves, and minute, sessile, 
moneecious flowers. Calyx with 4 short divisions. Petals 4in the male 
flowers, very minute or none in the females. Stamens in the males 8, 6, or 
4. Ovary and capsule of the females short, divided into 4 cells, with 1 seed 
in each. 
A small genus, widely diffused over almost every part of the globe. In 
_ its finely-cut whorled leaves it bears at first sight much resemblance to 
Ceratophyllum, but the lobes of the leaves are pinnate, not repeatedly 
forked as in the latter plant. 
Floralleaves or bracts not longer than the flowers . 1. M. spicatum, 
Floral leaves longer than the flowers, Heually pinaaie like the 
stem-leaves. ; . 2 WW. verticillatum. 
1. M. spicatum, ee (fg. 393). Spiked Myriophyll, Water Mil- 
foil.—Rootstock perennial, creeping and rooting in the mud under water. 
Stems ascending to the surface, but usually wholly immersed, varying in 
length according to the depth of the water, and more or less branched. 
Leaves whorled, in fours or sometimes in threes or in fives, along the whole 
length of the stem; the numerous capillary segments entire, 3 to near 6 
lines long. From the summit of the branches a slender spike, 2 to 3 inches 
long, protrudes from the water, bearing minute flowers arranged in little 
whorls, and surrounded by small bracts seldom as long as the flowers 
themselves. The upper flowers are usually males, their oblong anthers, 
on very short filaments, protruding from the minute calyx and petals. 
The lower ones are female, very small, succeeded by small, nearly globular 
or slightly oblong capsules, each separating ultimately into 4 one-seeded 
carpels. 
e watery ditches, and ponds, throughout Europe and Russian Asia. 
Extending all over Britain. £7. all summer. A slender variety, with 
the whorls of the spike often reduced to a single flower, and the lower 
ones having leaves at their base like the stem-leaves, has been considered 
by some as a distinct species, under the name of M. alterniflorum, D.C, 
2. M. verticillatum, Linn. (fig. 394). Whorled Myriophyll, Whorled 
Milfoil.—In deep, clear waters, the foliage is precisely that of I. spicatum, 
but the flowers are all immersed in the water, in the axils of the upper 
leaves. In shallow, muddy ditches, the segments of the leaves are often 
shorter and fewer, and the flowers form a spike protruding above the water 
as in MW. spicatum, but the bracts or floral leaves are longer than the 
flowers, and pinnate like the stem-leaves: this form constitutes the WZ. 
pectinatum of some authors, but cannot be distinguished with any precision, 
even as a variety. 
In watery ditches and ponds, with M. spicatum, over the greater part of 
its geographical range, and in many countries as common. In Britain it 
appears to be rather scarce, but perhaps frequently overlooked from its 
flowers not appearing above the water. 1. all summer, 
Il. HIPPURIS. MARESTAIL. 
A single aquatic species, distinguished as a genus from Myriophyllum 
by its entire leaves, and by its flowers always without petals, with a 
a 
