There are a lot of low-growing, blue-flowering aliens out there now, like the periwinkle I wrote about two days ago, or the mint family weeds I’ll be writing about next. Among these are the speedwells (genus Veronica, in the Plantaginaceae).
Of the 30 or so species of Veronica that can be found in North America, about two-thirds are alien. There may be as many as 17 species in Maryland; of these one may be native (sources vary), another is a fairly common native, and a third is a listed S1/Endangered native.
So if you find a speedwell in the field, it’s likely an alien. They can be pesky to distinguish, since in many cases close examination of the tiny leaves is necessary.
Trying to differentiate between bird’s eye speedwell (V. persica, pictured above) and ivy-leaved speedwell (V. hederifolia, sometimes spelled V. hederaefolia) was making me crazy, so I finally collected a few samples. In this picture, ivy-leaved speedwell is on the left, and bird’s-eye speedwell is on the right. The main differences are in the leaves. The former has leaves with 3-5 palmately compound lobes, hairy margins and hairy tops. The latter has much smoother leaves that are deeply indented (crenate or dentate).
This is V. hederifolia. Click on the picture for a closer look at just how hairy the leaves are.
This pretty awful picture from a few years ago shows just enough detail to identify the plant as corn speedwell, V. arvensis. The giveaway here is that the uppermost leaves are elongated, almost triangular in outline, with entire margins. The lower leaves of this species are rounder and toothed. Note its size compared to the blade of grass cutting across the upper left corner.
Here’s another old picture. Without details about the rest of the plant, I can’t say for certain, but it sure does look like the inflorescence of common speedwell, V. officinalis. As an aside, take a look at the flower. If you didn’t look closely and tried to key it out using Newcomb’s Wildflower Guide*, you could easily fall into the trap of calling it radially symmetrical, with four petals. But the bottommost petal isn’t the same shape as the others, which means it is bilaterally symmetrical; in Newcomb’s key it falls under “irregular”.
Last one. Again, I’m not certain, but the longish, smooth-margined, sessile leaves in pairs (more visible in other but worse pictures that I have) lead me to ID this as water speedwell, V. anagallis-aquatica. Another clue is habitat: I found it in a very wet, mucky area along the Potomac. It could also be American brooklime, V. americana, but in that species the leaves have more pronounced teeth along the margins, and the leaves have very short petioles.
I’m not an expert and had some trouble learning this genus, so if you disagree with any of my IDs please leave a comment!
*Newcomb’s Wildflower Guide is one of the best ID books for eastern North America flowers; the first question in the key is about symmetry.