FILAMENTOUS ALGAL SPECIES COMMON IN ACID AND SOFT WATERS.

Descriptions of operational taxa found in field studies in Scotland.

(Loch Ard area of The Trossachs, Galloway, Islay, Morar and Glenelg:
Kinross, 1985, 1991 and unpublished data)

LIST

Oedogoniales:
Bulbochaete  
Oedogonium

Taxon no. (1-50 as referred to in Kinross et al, 1993)

    Oedogoniales

52 = Bulbochaete

This has branched filaments with hair cells, but in contrast to the Chaetophorales the hair cells have a bulbous base and are unicellular. Each arises as an outgrowth of a cell alongside the neighbouring cell in the filament, like an abortive side-branch. Like Oedogonium, this genus shows sexual reproduction.

22-24 = Oedogonium species

The cells are slightly tapered so that the entire, unbranched, filament becomes wider with distance from the holdfast. Bulbous, oogonial cells may also be found and the cell walls bear ring-like scars due to the method of cell division. In some cases the narrowest filaments (approximately 6Ám diameter) may show little tapering and confusion is possible with other genera. Three size classes have been distinguished; 6 Ám, 15Ám and 30Ám. There is the possibility of overlap between the 15Ám class and the other two due to the tapering nature of the filaments so these are purely operational taxa.

In culture these taxa have been observed to produce zoospores, settle on substrata and grow for several days but have not continued to grow indefinitely.

22 = 6Ám:
23 = 15Ám:

For more illustrations look here (use the back button to return to this page).

[back to Algae in Acidified Streams]

Page updated 10/4/02

John Kinross