Can anyone tell me what this plant is? I originally thought it was a "tree fern", but a friend explained to me that if it doesn't have a trunk, it's not a tree fern. I still believe it is some kind of fern, but looking all over the internet I can't find a fern that looks like this one. It isn't hard to control using the clippers-and-trowel method, so I'm not looking for advice on chemicals to kill it. I am just curious what to call it.
Details: It seems quite happy here in Calif. (SF bay area) zone 9b. It never forms a central trunk, but just spreads out underground and covers an ever widening territory with new stems. Main stems start out green, furry, and sticky, round cross section, and they turn coppery colored with age. Stems never get thicker than about a half inch, and grow to a height of between 3 and 6 ft.
Edit Most of the IDs suggested here so far don't look to me like my fern because of the following additional info I neglected to mention before:
1) The texture of the leaves is not like many other ferns which have a brittle, shiny, plastic-y surface. These leaves are a little bit soft and slightly furry something like the texture of string-bean leaves.
2) The main stems have quite a length at the bottom which is bare, hairy but with no leaves attached, as shown in the last photo.
3) The growth habit of this plant is unlike most of the pictures I see on the internet of ferns that grow in dense clumps. My fern sends up single stems. They must be connected underground, but above ground they are all separated from each other by quite a few inches. Like this...
Here is a typical single frond that I cut off close to the ground. Total height is about 5'7", ground to tip.