Glossary - Freshwater Algae: Identification, Enumeration and Use as Bioindicators - page 256

Intercalary Arranged within a series of cells rather
than being at the end or alongside such as can occur
with heterocysts in blue-green algae

Marginal lines Lines of markings or clear areas
within markings running parallel to the margin of
a cell. Usually used in descriptions of markings on
certain diatoms

Iodine test The application of weak iodine solution
to starch produces a blue-black colour. Even in algae
producing starch as a food storage product the test
may not always give an obvious result as it depends
upon the physiological state of the cell, i.e. whether
it has been producing starch and how much

Marginal process Structures that occur around the
margin of a cell in some diatoms

Matrix The surrounding matter, especially

mucilage, to a cell

Median groove A groove or channel running
around the mid-region of a cell (as in dinoflagellates
where one of the two flagella occur in the median
groove which runs around the centre of the cell or in
some desmids where there is an indentation between
the two semicells)

Isobilateral Each side of the cell, as divided by the
longitudinal axis, is the same shape

Isopolar Both ends (poles) of the cell are the same
shape and size

Isthmus The narrow part of a desmid cell connect-
ing the two semicells

Metabolic Able to change its shape (as in some
species of Euglena ) as the cell wall is not rigid

Keel The channel or flange, sometimes raised on
ribsorstruts,inwhichtherapherunsinsomediatoms,
e.g. Surirella

Monospore A non-motile spore produced by the
monosporangium in Rhodophytes

Mother cell A cell that divides to form two or more
offspring (daughter cells)

L.A.B. Long as wide, used to compare length and
breadth dimensions of cells

Mucilage A material, often made of polysaccha-
rides, which swells in water and is slimy to tough

Lamellate Composed of layers (also laminate)

Lanceolate Lance-shaped, long and narrow with
a small increase in diameter in the mid-region and
tapering towards the ends

Multiseriate Composed of many rows

Nannoplankton Algal cells whose size is small
enough to pass through a plankton net

Lenticular Lens-shaped or hemispherical

Obliquely flattened Flattened at an angle, neither
horizontally or vertically

Leucosin A whitish food reserve characteristic of
many chrysophytes and usually found as highly
refractive rounded particles

Obovoid An approximate oval but with one end
(termed the anterior) wider than the other

Linear series A row of cells arranged side by side
in a straight line (for comparison see alternating
series)

Ocellus 'Eye-shaped' marking. A thickened
rimmed plate of silica with a number of pores on
its surface on a centric diatom valve

Lorica A shell or open flask-like structure which
the organism lies. The shape varies but there is always
an opening at one end, sometimes with a collar
through which a flagellum may pass

Ovoid Egg-shaped

Paramylum A solid starch-like food reserve found
in some euglenoids

Lunate Crescent or moon-shaped

Parietal Arranged at or around the wall of a cell

Mantle The marginal part of a diatom frustule,
joined to the epivalve or hypovalve

Pellicle A thin membrane covering a cell that has
no true wall