In case it's helpful to your research, there are matches to your posting found in Milwaukee's German newspapers: Regina (1881), Jacob Friedrich (1893), Jacob Sr. (1892), Ella (Maechtle) Hartman (1917), maybe others too.
The cemetery you refer to is called Town of Milwaukee Union Cemetery (now located in the city of Glendale, north of the shopping center). This can be confusing for researchers because of the other Union Cemetery located in the City of Milwaukee and the historic difference between city and township designations. The name "Union" in both cases refers to the union of different groups to create and maintain burial grounds.
The family is found with these different spellings: Maechtle Maechtl Mächtle Mächtl in "Milwaukee's German Newspapers; an index of death notices and related items" (1844-1950).
Gary Rebholz, originator/compiler/editor, Milwaukee Wis.firstname.lastname@example.org
Indexing Milwaukee's German newspapers continuously since 2007... helping family researchers collect contemporary evidence of their historic German-American culture.