POWO and World Plants consider Polygonum aviculare var. depressum to be a synonym of Polygonum arenastrum. While I understand that the taxonomy of the P. aviculare complex is still contentious, that one of these two taxa are a synonym of the other is does not appear to be, so only one should exist in the iNaturalist taxonomy.
Consider the community already seems to lean heavily toward P. arenastrum (see discussion in https://www.inaturalist.org/flags/608807), it seems appropriate to lean that way until someone publishes some additional information on the taxonomy of the complex.
Unintended disagreements occur when a parent (B) is
thinned by swapping a child (E) to another part of the
taxonomic tree, resulting in existing IDs of the parent being interpreted
as disagreements with existing IDs of the swapped child.
Identification
ID 2 of taxon E will be an unintended disagreement with ID 1 of taxon B after the taxon swap
If thinning a parent results in more than 10 unintended disagreements, you
should split the parent after swapping the child to replace existing IDs
of the parent (B) with IDs that don't disagree.
