Allow ambiguous records only in states where taxon occurs
In some cases records are treated as ambiguous for no apparent reason. For example, a search on Adiantum pedatum shows records from NCU, USDA, RAB and CVS. The NCU records are mapped as ambiguous, while none of those for the other sources are treated this way, even though all are for the same taxon.
This is NOT an error. The source of the confusion is that Weakley recognizes A. aleuticum as a segregate of the nominal A. pedatum, so all specimens of A. pedatum are ambiguous as to whether they are really A. pedatum or A. aleuticum. Other data layers are not ambiguous as they map to specific and unambiguous concepts.
Note that A. aleuticum occurs in our area only in MD. We have discussed having an improvement in the map generation algorithm such that a check is made on differences in ambiguity by state based on a list of which Weakley taxa are known for each state. If we were to implement this (which would take some time), then A. pedatum specimens would be ambiguous only in MD.
Updated by xianhua liu over 16 years ago
First, let me explain why Adiantum pedatum from NCU is ambiguous.
We have relationships:
1. Adiantum pedatum (Weakley 2005) = Adiantum pedatum (Kartesz 1999)
2. Adiantum pedatum (Weakley 2005) = Adiantum pedatum (Radford et al. 1968)
3. Adiantum pedatum ( Weakley 2005) < Adiantum pedatum (nominal)
Plus, RAB follows (Radford et al. 1968), USDA follows (Kartesz 1999), and CVS follows (Weakly 2005), while NCU follows nominal concepts. So when we search by concept Adiantum pedatum (Weakley 2005), based on relationship 1 and 2, all records from RAB, USDA and CVS are unambiguous, while records from NCU are abmiguous.
Secondly, if we treat weakley's concepts differently in different states, the taxonomic boundary of taxon concept is going to be blurred by geographic boundary. It may bring doubtness on the validity of the concept as a couple of scientific name and reference. If the definition of a concept is location-dependent, the current assumption that a concept is uniquely definied by its scientific name and reference will become questionable.
I am not sure if I understood the issue correctly. Please correct me if I am wrong.