THE AMERICAN BOTANIST. 87 
to have developed an arborescent or tree-like group simi- 
lar to the bamboos. The family likeness is plainly 
stamped on most of the species which are thus made 
easily distinguishable from grasses ; but in some cases the 
young student is likely to vote the likenesses altogether 
too close as in the genus Cyperus with four hundred 
species or the genus Carex which contains about seven 
hundred ! 
As a whole the Cyperaceas seem to be a bit easier to 
identify than the grasses. The flower approaches more 
closely the typical monocotyledon flower, having in some 
cases a whorl of six perianth segments, six stamens and a 
pistil composed of three carpels. There are seldom more 
than three stamens, however. The perianth segments 
may be slender and bristle-like or short and broad. In 
Eriophorum the many cottony hairs are regarded as 
parts of a perianth. Other members of the group have 
flowers quite devoid of a perianth as in Carex. In this 
latter genus the staminate and pistillate flowers are in 
separate heads and the pistillate are surrounded by a 
bottle-shaped sheath called a perigynium. Some regard 
this as the equivalent of a perianth but the modern view 
makes it a bract such as subtends the flower in other 
members of the Cyperaceas. 
The flowers are small, green, inconspicuous and as 
may be assumed pollinated by the wind. The majority ^ 
as in the grasses, avoid self-pollination by ripening pistils 
and stamens at different times when the two organs occur 
in the same flower. In others, as Carex, the two kinds of 
essential organs are in separate heads and often on sepa- 
rate plants, thus necessitating cross-pollination. The 
stigmas are seldom feathery as in the grasses, though the 
flowers are wind-pollinated. The fruit is a triangular or 
lens-shaped achene or utricle, depending entirely upon 
whether the pericarp closely surrounds the seed or is 
inflated. In structure the Cyperaceee may be distinguished 
from the Gramine£e by their solid, usually triangular, 
stems, their long, narrow, three ranked leaves springing 
