Ask Mr. Smarty Plants

We found the previous answer from Mr. Smarty Plants you were apparently referring to. The two plants in that answer that had the common name of "crow's foot" were Lycopodium digitatum (fan clubmoss) and Sedum ternatum (woodland stonecrop); a sedum. Both of these plants are known to be native to Pennsylvania; however, it is the Fan Clubmoss that looks most likely to be a candidate for a Christmas wreath. From our Native Plant Database page on this plant: "Formerly gathered for Christmas decorations, but deforestation made it too rare to be used."

That tells you that it shouldn't be used, certainly, but it doesn't tell you if you will be fined for using it. We checked the Pennsylvania Department of Conservation and Natural Resources website on Endangered Plants of Pennsylvania but did not find it there. According to this USDA Plant Profile, it does, indeed, appear to grow all over the state.  We tried to find some official source that might be able to tell you more about penalties for gathering this plant; this is usually a ruling for a particular area but we are unaware of an authority in Pennsylvania that could administer such a rule. The responsible thing, in view of the information above, would be to leave it to re-establish itself, but we doubt there are clubmoss police out in the woods ready to put on the handcuffs if you pick some.

From our Native Plant Image Gallery: 

Lycopodium digitatum