Selenastrum - a colonial algae

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NikonUser
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Joined: Thu Sep 04, 2008 2:03 am
Location: southern New Brunswick, Canada

Selenastrum - a colonial algae

Post by NikonUser »

Small colonial algae with sickle-shaped cells arranged irregularly in 3-planes.
5 species in USA differentiated by size of cell and degree of curvature measured by distance between apices (1970 ref.) (about 10µ in this species).

Top: Full frame image, 60x Nikon oil obj. on Olympus scope with Olympus 2.5x NFK relay lens (not the best configuration).
Bottom: enlargement.

These algae are relatively uncommon in my overwintering pond sample.

Posted here as an example for the genus; no other images on PMG.net.

Image
Image
NU.
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.

Nikon camera, lenses and objectives
Olympus microscope and objectives

Song miae
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Post by Song miae »

good pictures :D
I can't distinguish Selenastrum and Ankistrodesmus :(
I love taking pic. And all of the algae.

Mitch640
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Joined: Sun Aug 15, 2010 1:43 pm

Post by Mitch640 »

If and when I ever get any algae here, I am going to know what some of them are when I see them, thanks to your posts. :)

NikonUser
Posts: 2676
Joined: Thu Sep 04, 2008 2:03 am
Location: southern New Brunswick, Canada

Post by NikonUser »

Selenastrum are strongly crescent-shaped, as in my image, and closely clustered.
Ankistrodesmus are much straighter or only slightly crescent-shaped, often loosely entangled and frequently solitary.

Mitch:
In anticipation of you finding lots of algae you will find the following book a great help (if you can find a copy):
Prescott, G.W. 1970. How to Know The Freshwater Algae. 2nd Edn., maybe later editions available.
Has keys and lots of excellent line drawings; includes some desmids and some diatoms. Highly recommended.
NU.
student of entomology
Quote – Holmes on ‘Entomology’
” I suppose you are an entomologist ? “
” Not quite so ambitious as that, sir. I should like to put my eyes on the individual entitled to that name.
No man can be truly called an entomologist,
sir; the subject is too vast for any single human intelligence to grasp.”
Oliver Wendell Holmes, Sr
The Poet at the Breakfast Table.

Nikon camera, lenses and objectives
Olympus microscope and objectives

Mitch640
Posts: 2137
Joined: Sun Aug 15, 2010 1:43 pm

Post by Mitch640 »

I have already spotted some of these in Johns Algae Tapestry thread. I did find a desmid a few months back, but it was tattered and not healthy looking, and, partly angled, so it was mostly out of focus.

http://www.photomacrography.net/forum/v ... hp?t=12690

twebster
Posts: 442
Joined: Wed Jul 26, 2006 8:02 am
Location: Phoenix "Valley of the Sun", Arizona, USA

Post by twebster »

This is a very interesting algae. I would not have guessed these are colonial. Looks like a loose gathering to my eyes. Thanks for the additional details.
Tom Webster

Phoenix "The Valley of the Sun", Arizona, USA

The worst day photographing dragonflies is better than the best day working! :)

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