I say fungus too. It usually looks more like cobwebs, but that's not carved in stone. I recently had to send back a Lentar 300 that had fungus in the rear lens, when I removed and tried to clean it I got the fungus but found it had etched the lens, and it looked more like a fingerprint smudge than anything else. Tiny roundish spots in fairly straight, parallel lines.
Oh hell, here's a picture, I can't describe it well enough. The scratches are on the other side of the lens and from someone's botched cleaning attempt before I got it. Probably from a grubby t-shitrt...
I've seen other pictures, and have a Pentax 50mm with fungus that looks more like cobwebs or in some cases looks like a drop of oil in a pan of water. Fungus grows according to its own pattern, which depends on which of thousands of varieties of fungus it happens to be. In your yard or in the woods it looks like mushrooms...on a slice of bread it grows in round blue or black spots...
Anyway, in the picture above, that's the etching it left behind. I neglected to take a "before" picture, it was white and just looked like a foggy spot. SO I thought it was a smudge from a previous cleaning attempt, and when I removed the lens, (quite easy to do, just unscrew the rear barrel section) I found out it was on the inside and cleaned off pretty easy with acetone. But the etching you see above remained. I would have never guessed fungus...but the only other thing I know of that will etch lens glass is fingerprints, and this is not curled enough to be a fingerprint, it's fairly straight lines. You don't have any lines that straight in your fingerprints...not that long anyway. That lens is 1 1/4 inch in diameter and it goes all the way across. The only place a person's hand could do that would be across the palm, in a couple of places.
I think the lens in question has fungus. If you can remove the front element, it's probably just one lens, it would require removing the front retainer ring. That's the ring with the lens brand and focal length printed on it. Since they usually have no slots for a spanner tool, it's not easy and you risk gouging it, but it can be removed with either a special tool or something with a point to turn it with. I wouldn't recommend trying it if you aren't familiar with the procedures required and don't have the right tools.