[CentOS] Yum list installed lies to me

when I do "yum list installed" I get a lot of stuff, including this excerpt:

wqy-zenhei-fonts.noarch                       0.9.46-11.el7                       @anaconda       
wvdial.x86_64                                 1.61-9.el7                          @anaconda       
wxBase.x86_64                                 2.8.12-20.el7                       @epel           
wxBase3.x86_64                                3.0.2-15.el7                        @epel           
wxGTK.x86_64                                  2.8.12-20.el7                       @epel           
wxGTK-gl.x86_64                               2.8.12-20.el7                       @epel           
wxGTK-media.x86_64                            2.8.12-20.el7                       @epel           
wxGTK3.x86_64                                 3.0.2-15.el7                        @epel           
wxGTK3-debuginfo.x86_64                       3.0.2-15.el7                        @epel-debuginfo 
wxGTK3-devel.x86_64                           3.0.2-15.el7                        @epel           
wxGTK3-gl.x86_64                              3.0.2-15.el7                        @epel           
wxGTK3-media.x86_64                           3.0.2-15.el7                        @epel           
wxPython.x86_64                               2.8.12.0-9.el7                      @epel           
x264.x86_64                                   0.142-11.20141221git6a301b6.el7.nux @nux-dextop  


however if I do:

yum install wxWidgets wxWidgets-devel

it says:

Package wxGTK3-3.0.2-15.el7.x86_64 already installed and latest version
Package wxGTK3-devel-3.0.2-15.el7.x86_64 already installed and latest version

so this is confusing to my feeble old brain: what's going on here?

-- 
---- Fred Smith -- fredex at fcshome.stoneham.ma.us -----------------------------
  "For him who is able to keep you from falling and to present you before his 
 glorious presence without fault and with great joy--to the only God our Savior
 be glory, majesty, power and authority, through Jesus Christ our Lord, before
                     all ages, now and forevermore! Amen."
----------------------------- Jude 1:24,25 (niv) -----------------------------