Does this look like mold?

Ray, it doesn't llok like typical fungus. I'd guess it's just a normal buildup of dust. From my personal experience that much, while looking significant , wouldn't cause an appreciative loss in image quality.... maybe some contrast difference and perhaps some flare in extreme lighting situations.

This is what lens fungus looks like (tell-tale cobweb pattern)... and even this much is hardly noticeable in regular photos. You'd be more concerned about the odd speck of dust on your sensor than some little grungy blobs between your glass.

Thank you for your help!
I'm usng a film camera, so there's no sensor. This lens is old and is from my grandfather, should i go get it cleaned to prevent molds?
thanks

Ray, I guess it's for an Exakta , maybe ? I'm sure you wouldn't notice much at all if you run a roll of film through the camera with this lens on. Just give the outer elements a good cleaining yourself, put on a lens hood if you have one, and head outdoors and take some snapshots.
As for PREVENTING mold : always store lenses and camera gear in a dry, room-temperature place with a few packs of dessicant ( Silica Gel) in the case, camera bag, or wherever you store your stuff. It's darkness and mosisture that these critters like.
Sometimes setting a fungus-infested lens in the sun for a couple of hours helps. Only disassembly and proper cleaning will eliminate fungus most of the time.

The rear element and the front element come off easily. They are held by threaded rings. So you can clean about 6 surfaces easily. I would hope that most of the dust would come off with that effort. This lens is of top quality. Most certainly worth cleaning and keeping. Best, sp.

In any case: Is fungus really so bad?
I mean; My lens sometimes get really dirty (well, the filters), I even used filters full with grease spots and I didn't notice any difference. I know that fungus eats up the lens coating... but for a B/W photog that uses filters anyway... is this really a concern?

One of the byproducts of fungus growth and "activity" is some kind of exuded stuff that eats into some photographic glass. In other words, if you leave fungus in place for too long, and it is active enough, it'll eat into the glass itself, leaving a bas-relief sculpture of itself behind even after cleaning.

If there's enough of it, it'll degrade the image. At the very least, it'll cause some flare.

In any case: Is fungus really so bad?

Bad if you're trying to sell an otherwise good piece of glass. Great if you're looking for bargain optics.

I posted some photos of the Nikkor's fungus, Ray, if you're interested.
http://www.flickr.com/photos/ebanator/sets/72157622870749583/

Has anyone ever grown fungi in a lens on purpose to achieve special effects in the image?