Problem Plant

Day 236: Field guides and even professional-level plant manuals tend to focus their descriptions on the characteristics of the inflorescence, making it difficult to determine the identity of a plant based solely on foliage. Fearing that my yard was infested with Garlic Mustard (a Class A invasive), I have been diligently pulling it for years, never allowing it to come into bloom. But something bothered me. For one thing, it pulled relatively easily and the roots did not appear to have the characteristic bend found in Alliaria petiolata. I did not recall having seen first-year rosettes, and the leaves did not smell the least bit garlicky when crushed, no matter how hard I sniffed. Then I happened to notice the two "wings" below the main portion of the leaf, and I began to suspect that perhaps the plant wasn't Garlic Mustard after all. I made a point of pulling a complete specimen and brought it in the house for closer examination. No, it didn't appear to be Alliaria, but if not, what was it? With no flower to analyze, Hitchcock was no help. I tried assuming that it was a crucifer like Garlic Mustard and got nowhere, so I finally sent my photos to Arnie and David Giblin at WTU. Both of them replied with a possible identification of Lapsana communis, with Arnie adding that he'd observed Lapsana in my general area. The description of the foliage in Hitchcock matched perfectly, and I was surprised to note that it has a yellow composite flower resembling a smaller version of the hawkweeds. But...and here's the clincher...it's still a pernicious weed, if not to quite the same extent as Garlic Mustard.