Page 4 - at-winter-microscopy-pdf

Species in the Fig. 6. Cosmarium spp. showing some of the variety of forms
genus
Cosmarium vary
considerably in
shape, seemingly
double-celled they
actually consist of
two semi-cells
(Fig. 6). The semi-
cells appear flat
but when seen
from the apex or
side (difficult to
see these
aspects) they are
oval or elliptical in
outline. Various
levels of focussing
are necessary to
see either the
external cell wall
which may be
smooth, granular,
or have short
conical warts, as
seen in the bottom
left image of Fig.
6, or the internal
structures. The
cell nucleus is in
the center
between the two
semi-cells.