Bambusina Kützing
Cells are nearly cylindrical or barrel-shaped, with a slight median
constriction, often swollen above and below the isthmus and joined
by their flat ends to form slightly twisted filaments. Bambusina
brebissonii is the type species. (Croasdale, H., Flint, E. & Racine,
M. 1994. Flora of New Zealand Desmids III. - Landcare Research
New Zealand Ltd.)
Closterium Nitzsch ex Ralfs
Cells are solitary, not medianly constricted, mostly regularly
curved and tapered toward both ends. Cellwall smooth or striate.
True girdle bands present in some species. Semicells with a single
axiale chloroplast, showing longitudinal ridges and one to many
large pyrenoids usually in a median row, but in larger species
scattered. (Croasdale, H. & Flint, E. 1986. Flora of New Zealand
Desmids I. - Wellington Gov. Print.)
Cosmarium Corda ex Ralfs
One of the most species rich desmid genera with >1200 species.
It lacks distinctive features similar to those defining other
genera and it is often based on negative characters. Some basic
characters: end view often compressed, absence of spines, apex
of cell neither cleft nor indented, cells solitary. (Croasdale,
H. & Flint, E. 1988. Flora of New Zealand Desmids II. - Caxton
Press, Christchurch.)
Desmidium C.A. Agardh
Cells joined to form twisted or rarely straight filaments, sometimes
enveloped in a mucilaginous sheath. Cells usually broader than
long, often compressed, with distinct but only moderate deep constrictions.
(Croasdale, H., Flint, E. & Racine, M. 1994. Flora of New Zealand
Desmids III. - Landcare Research New Zealand Ltd.)
Euastrum Ehrenberg ex Ralfs
Cells longer than broad, compressed, deeply constricted at isthmus
with sinus usually closed. Cells are characterized by an apical
notch which is absent only in a few species. (Croasdale, H. &
Flint, E. 1986. Flora of New Zealand Desmids I. - Wellington Gov.
Print.)
Micrasterias C.A. Agardh
Cells are large, flat approximately circular, with a deep median
incision. Semicells are divided into a polar lobe and two lateral
lobes which may be divided again. The large beautiful members
of this genus have been the object of much research. (Croasdale,
H. & Flint, E. 1986. Flora of New Zealand Desmids I. - Wellington
Gov. Print.)
Pleurotaenium Nägeli
Cells usually solitary but rarely joined end to end in fragile
pseudo-filaments. Cells straight, mostly cylindrical, in the middle
slightly constricted, often with one or more inflations above
the isthmus, the sides above smooth, undulate or nodose slightly
tapering to the apex. The apex is rounded-truncate and in some
species ornamented with a circle of polar nodules. (Croasdale,
H. & Flint, E. 1986. Flora of New Zealand Desmids I. - Wellington
Gov. Print.)
Staurastrum Meyen
Cells are always solitary, radially symmetrical and divided in
2 semicells. In end view cells are tri-pluriradiate, rarely biradiate.
Cell wall porous and smooth or ornamented with spines, granules,
teeth or verrucae. Cells often surrounded by spherical, mucilaginous
envelope, especially in planktic species. (Croasdale, H., Flint,
E. & Racine, M. 1994. Flora of New Zealand Desmids III. - Landcare
Research New Zealand Ltd.)
Staurodesmus Teiling
The species are unicellular, the sides of the semicell are extended
laterally into angles which end in a spine, mucron, wart or papilla.
The cell wall is smooth or punctate but never granular or aculeate.
Many species are planktic. (Croasdale, H., Flint, E. & Racine,
M. 1994. Flora of New Zealand Desmids III. - Landcare Research
New Zealand Ltd.)
Xanthidium Ehrenberg ex Ralfs
Cells generally ranging from 35 to 70 µm in length and little
less in breadth. Cells are often furnished with simple often paired
spines, usually arranged more or less symetrically on the lateral
margins. (Croasdale, H. & Flint, E. 1988. Flora of New Zealand
Desmids II. - Caxton Press, Christchurch.) |
