Juncus balticus has fine wiry bright green culms and tiny dark brown flowers that give the garden a speckled look (which I happen to like very much). It grows well in clay and in the coastal prairie.
(in front of tufted hairgrass)
Juncus ensifolius, which has bright green iris-like foliage and black balls of flowers. I sometimes call it Poodle Rush after my mom's little black poodle. It's very ornamental, but can get a bit weedy looking toward the end of the season. It may need to be cut down to the ground each year (I did that laster year and it helped) and it's spreading may also need to be controlled (easy enough in the bog).
This bluish rush is called Juncus patens, or the California Grey Rush. This has a very dark appearance in the landscape and is very rigid and upright. It's flowers are in brown clusters with touches of red and orange.
Then there is Juncus effusus, the softstem rush. This one looks like a more rubust and upright J. balticus, and can get much taller (four feet max?). These bareroot clumps are just sitting in the fountain for the time being, so they're not much to look at.
As you can see in this cross sectional comparison, the culms of J. effusus are also much thicker than J. balticus.
One day I was reading in one of my favorite books, The Once and Future King by T.H. White and he mentioned a "rushlight." Looked it up on wikipedia and read this magazine excerpt and it turns out that old Brits used the pith of J. effusus (yes, it's also native to the British isles) as a wick for candles they called rushlights. Read the magazine excerpt for details. I'd like to try my hand at making rushlights, but I don't have a supply of household grease or bees wax. Not yet anyway.
The green tissue is easy to peel from the pith. The pith, by the way, feels and looks like a spaghetti noodle made of plastic packing foam.
Also in the yard are annual Toad Rushes that are weedy and hairy wood rushes (Luzula spp.) that are also in Juncaceae.
My hope is to encourage everyone to look a bit more closely at "grasses" because there's tons of diversity there. I haven't even gotten to the other graminoids such as the bulrushes, spike rushes, and sedges.