Paulownia [桐, kiri] is the name of a suit in traditional hanafuda decks. It is generally taken to be the twelfth and final suit, representing the month of December [12月, jūnigatsu] or the number 12.
The cards in this suit all feature large paulownia leaves with purple flowers and capsules. There are three Chaff cards and one Bright. The Bright card features a purple and red Phoenix [鳳凰, hōō] above the paulownia plant, with the area below the plant generally colored yellow.
One of the three Chaff cards generally has a yellow (sometimes red) area below the paulownia, which may be used to distinguish it from the other two for the purpose of some games. Some combination of these three cards usually feature the name of the deck’s manufacturer, that company’s logo, and/or other information about the deck.
In a few games, including Tensho, an alternate month ordering is used, with the Paulownia suit representing June or the number 6 instead. On the other hand, in the Korean suit order, Paulownia is considered to represent November or the number 11.
For examples of traditional art with the same motifs as this suit of hanafuda, see also the following category on Wikimedia Commons: