Interesting ID Problem: Geum, Duchesnea or Potentilla?

[Andrea B.]

That is a nice set of maps, isn't it?

 

I had checked early on in the Michigan Flora linked above to make sure the various possibilities could be found in that state.

 

The P. intermedia we are referring to above is a hybrid of P. argentea and P. norvegica, both also found in Michigan. It shouldn't come as a surprise that Zach's flower is showing characteristics between P. intermedia and P. norvegica. And that one of my other initial guesses was P. argentea.

 

Usually I run into this kind of intergrade when trying to key the Horrible Hieracium. Potentilla can apparently also be difficult.

[nfoto]

At present, Potentilla cf. norvegica is the feasible name according to the information at hand.

 

Flora Europaea (vol.2) says P. intermedia can have ternate basal leaves although 5 (palmate) is more common. Also states P. norvegica can have petals as long as the sepals although they usually are much shorter, in P. intermedia they are at least as long as the sepals. The epicalyx segments ('bractlets' in US floras) are longer than the sepals in P. norvegica and about the same length in P. intermedia, but be aware they extend when the flower matures and goes to fruit. P. intermedia can be glabrous or nearly so at the basal part of the plant, whilst P. norvegica is hairy all over.

 

Linnaeus (1753) did not recognise any hybrids and just described P. intermedia as intermediate between P. norvegica and P. recta. European P. argentea is usually apomictic and as such is not involved in hybridisation.

[Andrea B.]

I will work with Zach to make the necessary changes on his post.

 

This has been a very interesting discussion, hasn't it? This must be one of the trickiest IDs we have run across so far.

[msubees]

Strangely, according to this map, neither P. intermedia nor P. norvegica is in Michigan?

 

Distribution maps any help?

http://bonap.net/NAP...unty/Potentilla

[Andrea B.]

The map for a flower is above its name.