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(b) Cells spaced apart within a colourless
mucilagematrix.......................
73
72
(71) (a) Chloroplast green and cup-shaped, stor-
age product starch. Cells, embedded in
mucilage that obviously extends beyond the
cells at the colony edge, have two equal-
length flagella.. ...............
Pandorina
Colonies of
Pandorina
are spherical to oval
in shape with 8-16 (32) densely packed cells.
Individual cells (8-20 μm long) have flat-
tened sides where they touch their neigh-
bour and also slightly flattened apices. On
the outside of the cells is a wide band of
mucilage through which the flagella pro-
trude. The colony centre is not hollow. Indi-
vidual cells may divide to form daughter
colonies which are later released. Colonies
swim with a tumbling motion through the
water. Common in the plankton. Reported
to impart a fishy odour to drinking water
(Palmer, 1962). Chlorophyta. Plate X. Figs.
1.3 and 4.36.
50 μm
Figure 4.35
Aphanocapsa
. Low power view of
colony. Olive-brown cells of this alga are widely
dispersed within the copious mucilage. A range of
other algae and bacteria are also present. Indian ink
preparation.
69
(68) (a) Cells of the colony with flagella, colony
motile................................
70
NB.
It is important to look at fresh speci-
mens to determine the presence or absence
of flagella as they may be difficult to see in
preserved samples.
(b) Cells of colony without flagella, colony
non-motile . . .........................
76
70
(69) (a) Each cell is enclosed in a flask-shaped
lorica, narrow and pointed at one end, wide
attheother...................
Dinobryon
20 μm
(see also key No. 7)
(b) Cells not located in a lorica. ........
71
Figure 4.36
Pandorina
. Colony showing densely
packed cells with surface mucilage through which flag-
ella protrude (arrows). Reproduced with permission from
R. Matthews.
71
(70) (a) Adjacent cells touching in densely
packed colonies. ......................
72
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