One of those stands of irises that I keep writing about is in a depression in the woods that in most years is a vernal pond. Last year was dry, though, and the rain we’ve had so far this year doesn’t seem enough to bring groundwater levels back to normal.

At any rate, that sometimes-vernal pond has only a few irises, but it’s absolutely dominated by this plant.

This is Saururus cernuus, commonly known as lizard’s tail, water dragon, and breast weed. It’s a wetland obligate, meaning that it grows almost exclusively in wetlands.*

There are two other stands I know of, one near the Carderock climbing wall, and the other near the Old Angler’s Inn footbridge, which is where I took these photos. This stand seems to be in shade for much, but not all, of the day, while the other stands are pretty much in full shade, all the time.

Lizard’s tail forms large colonies by rhizomes. The plants stand up to three feet tall, with large, heart-shaped leaves and curved spikes of white flowers. Each flower consists of stamens and a single pistil, without petals or sepals.

Saururus is a genus with only two species; the other, S. chinensis, is native to Asia. The Saururaceae is a small family, with only seven species in five genera. S. cernuus ranges from Texas to Quebec, though it’s missing from much of New England. In Maryland it’s found in every county except for Frederick and Garret; I wouldn’t be surprised if it grows in those places as well, but no one’s reported it yet. It’s endangered in Connecticut and Rhode Island, but listed as weedy by the Southern Weed Science Society.

For once, the common name has some relation to the botanical name: Saururus is from the Greek words sauros (lizard) and oura (tail). The specific epithet cernuus means nodding or drooping.

*official definition: Plants that occur almost always (estimated probability >99%) in wetlands under natural conditions, but which may also occur rarely (estimated probability <1%) in non-wetlands (from forestandrange.org )