Bitterblossom

• WWizards of the Coast2008-04-01
  Official Ruling
  The life loss isn't a payment. You'll get a token even if you had 0 life (and another effect is stopping you from losing the game).
• WWizards of the Coast2008-04-01
  Official Ruling
  The effect is mandatory. You'll lose 1 life even if you have only 1 life left.
• WWizards of the Coast2024-06-07
  Official Ruling
  While it appears only on cards that already have other card types, kindred is a card type and will be counted by effects that refer to the number of card types among cards in a zone.
• WWizards of the Coast2024-06-07
  Official Ruling
  Kindred is a card type that allows noncreature cards to have creature types. For example, Echoes of Eternity is an Eldrazi (although not a creature) while on the battlefield and an Eldrazi card (although not a creature card) in zones other than the battlefield.
• WWizards of the Coast2024-06-07
  Official Ruling
  This cards was originally printed with the "tribal" card type. That card type has been replaced with "kindred". This change does not affect the gameplay function of this card.

Rulings via Scryfall

• WO
  Wizards of the Coast2015-02-03

  Bitterblossom was unbanned in modern on February 3, 2015. The second round of unbannings sought again to diversify the format. Bitterblossom has since taken its place in the Modern metagame, but has yet to truly break out again. Source: https://magic.wizards.com/en/news/arcana/brief-history-modern-banned-list-2015-02-03
• WO
  Wizards of the Coast2015-02-03

  Bitterblossom was banned in modern on February 3, 2015. Modern kicked off with a banned list that was created in large part based on Legacy play, the old Extended format, and decks played at the Community Cup that year. We are going to allow turn-four combination decks, but not decks that consistently win the game on turn three. Source: https://magic.wizards.com/en/news/arcana/brief-history-modern-banned-list-2015-02-03
• WO
  Wizards of the Coast2014-02-03

  Bitterblossom was unbanned in modern on February 3, 2014. At the time of Modern's inception, we took the conservative approach of including Bitterblossom in the initial banned list. After observing the evolution of the Modern format, we feel that it is of an appropriate power level to compete with the other powerful strategies in the format. Source: https://magic.wizards.com/en/news/top-decks/february-3-2014-dci-banned-restricted-list-announcement-2014-02-03