Worldwide there are almost 1,700 species of Potentilla. More than 80 can be found in North America, four of which are in the Maryland Piedmont, including dwarf cinquefoil and common cinquefoil. There are five in Iceland.
those fleshy leaves–>
belong to another plant;
the potentilla leaves are
formerly Argentina anserina
Providing stats for Potentillas is tricky, as there have been a lot of name changes recently. One of the older names for P. crantzii is Fragaria crantzii. The two genera are very closely related, so I’ve included this plant as well:
Yep, that’s good old strawberry (one of them, anyway). You can see a bit of the leaves on the lower right. The grassy looking stuff the flowers are poking through is horsetail (Equisetum species).
Back to silverweed: it can be found across the temperate regions of the northern hemisphere, and in most of North America except for the South and lower Midwest. It’s widespread in Iceland.
Alpine cinquefoil is limited in North America to northeastern Canada and Greenland. In Iceland it grows near rivers and the seashore.