The German parties have colours associated with them. Red is SPD, green is the Green Party (Die Gruenen), Black is CDU/CSU, F.D.P. is yellow (and blue), PDS is dark red.
Rot-Grün is another name for the reigning coalition on federal level.

The political parties represented in the Bundestag are:

-- The Social Democratic Party (SPD), which abandoned the concept of a strictly working class party in 1959 while continuing to stress social welfare programs. The SPD heads the federal government that took office in October 1998 under Chancellor Schroeder.

-- The Christian Democratic Union and its Bavarian sister party, the Christian Social Union (CDU/CSU). The CDU/CSU is generally conservative on economic and social policy.

-- The Alliance 90/The Greens (Buendnis 90/Die Gruenen), which has an environmentalist, pacifist platform, is the junior partner in the current federal coalition government.

-- The liberal Free Democratic Party (FDP) identifies itself as a market-oriented, civil libertarian party.

-- The Party of Democratic Socialism (PDS), which is the successor party to the communist party of the former German Democratic Republic -- the SED.

For a quick explanation about the political orientation of the various German parties see the above web site.