Tuesday, November 3, 2009

What's This? Justin Knows!

I recently posted this photograph as a plant quiz...


It is difficult to post a quiz on this blog that lasts more than a day without an answer. Justin correctly identified the mystery seedling in the photograph above as Penthorum sedoides. Ditch Stonecrop, as it is commonly known, is native to wet meadows, marshes, ditches, and muddy shores throughout the eastern half of North America, and has been introduced in the Pacific Northwest. Once accepted as a member of the family Saxifragaceae, it seems that most authorities now place this interesting plant in the family Crassulaceae; some even put it the Penthoraceae. As this species matures, it produces greenish-white, inconspicuous flowers; the flowers develop into attractive reddish follicles with spreading beaks, shown below. Penthorum means "five-mark," a reference to the five-parted flowers, and sedoides means "resembling Sedum."


Nice work, Justin.

5 comments:

Keith said...

How about Proserpinaca palustris?

Scott said...

I can see how you might think this, but that's not what it is. I believe that Proserpinaca palustris would have highly dissected leaves as a seedling (and would look more like a Myriophyllum).

Justin Thomas said...

My brain keeps saying Penthorum sedoides, so what the heck.

Keith said...

I seem to recall that the highly dissected (feathery) leaves on Proserpinaca palustris develop under water mostly, while emergent leaves and those of stranded plants are mostly just dentate. Am I mis-remembering that? It seems like seedlings could possibly have dentate leaves, as well. However, I'm not still trying to say that your mystery plant is Proserpinaca.

Scott said...

Keith, you're right that the dissected leaves of Proserpinaca palustris develop when submerged. That said, I'm not sure that I've ever seen it growing in an area that was not inundated early in the year (not to say that it wouldn't). I think you could still separate the two based on stem color (Penthorum sedoides has a reddish stem, even when a seedling, while I believe that Proserpinaca palustris has a green stem). Also, the leaf arrangement of Penthorum sedoides seems pretty characteristic (alternate, but radiating in all directions when viewed from above). I don't know if Proserpinaca palustris would have the same arrangement or not.