Akodon spegazzinii is found in northwestern Argentina, in the provinces of Salta, Catamarca, Tucumán, La Rioja, and Mendoza, at altitudes of . Although its main distribution is in the northern provinces of Salta, Tucumán, and Catamarca, there are also scattered records from the more southern provinces of La Rioja and Mendoza, where it is likely restricted to patches of wet habitat. "Akodon alterus" has been reported from Jujuy, but this record was likely based on misidentified specimens of "A. boliviensis", and records of "Akodon spegazzinii" from Jujuy were based on misidentified "A. sylvanus". "Akodon spegazzinii" is known from a paleontological site in
Dicentra formosa has narrower flowers and longer, more curved outer petal tips. "D. formosa" is related to "Lamprocapnos spectabilis", another popular plant called "bleeding heart", which was formerly placed in the same genus. The Pacific bleeding-heart is native to moist woodland, forest, and streambanks from California to British Columbia, from sea level to the subalpine zone. There are two subspecies, "Dicentra formosa" subsp. "formosa" and "Dicentra formosa" subsp. "oregona". Subsp. "formosa" grows in the majority of the plant's range, from Vancouver Island and southern British Columbia and south through Washington and Oregon to central California in the Coast Ranges and Cascades, and