From the Super Mario Wiki
“Screaming pulsars! What in the universe is that thing?! It looks like a flower with a face! Wow... It's a Fire Flower? Hrm... Well, I gotta say there, you collect some of the most interesting stuff I've ever seen!”
Fire Flowers are a power-up that appear in many games in the Mario series, originating from Super Mario Bros. They can be found inside blocks (mostly ? Blocks) that normally contain Super Mushrooms if the player is already in their Super form (or in later games any other powered-up form), and obtaining one transforms the player into their Fire form, allowing them to throw fireballs. The Ice Flower is the polar opposite of the Fire Flower.
Super Mario series
Super Mario Bros.
In Super Mario Bros., if Mario collects a Fire Flower, he will get the ability to shoot fireballs by pressing . The fireballs may be a strong and handy projectile to use because it defeats most enemies and even Bowser from a range. Only two fireballs may be thrown at once. If Mario gets hit while he is in this form, he will revert back to Small Mario. If Small Mario gets a Fire Flower, he will only transform into Super Mario.
Super Mario Bros.: The Lost Levels
Fire Flowers return in Super Mario Bros.: The Lost Levels, granting Mario the same ability and retaining the same appearance as Super Mario Bros.
Super Mario Bros. 3
In Super Mario Bros. 3, they are the third most common power-up, the first being a Mushroom and the second being a Super Leaf. They, like before, grant Mario the ability to shoot fireballs. Not much has changed since Super Mario Bros. regarding their function; they can still defeat Bowser, although he can withstand many more fireball hits than his original incarnation.
The American version of this game introduced the idea that Fire Mario reverted back to Super Mario upon being hit, rather than Small Mario, as in other games. This was retained in all subsequent releases of this game.
Super Mario World
In Super Mario World, Fire Flowers receive a change in appearance. They appear as happy red tulip-like plants, and originaly planned to appear with circular appearance like in the other games. Other than this change, nothing has been changed in function.
This game introduces the idea of storing powerups, having the previous one released when Mario is hit by an enemy when in a super powered form. Because of this, Fire Mario reverts back to Small Mario in the SNES version, as he can get the Super Mushroom (or better) that he had before. Additionally, because of the added feature of spin-jumping when Mario does so by pressing , he shoots out fireballs left and right while in the air.
In the Game Boy Advance version, Mario retains the new setup added on by Super Mario Bros. 3. Fire Mario immediately becomes Super Mario upon being hit.
In previous games, if Small Mario grabbed a Fire Flower, he would become only Super Mario. This is the official first game in which he can bypass the Super form and become Fire Mario right away. (Super Mario Bros. 3 allows Small Mario to morph straight to Fire Mario, but only through a glitch.)
New Super Mario Bros.
In New Super Mario Bros., Fire Flowers can be considered stronger, or weaker. A large amount of enemies are immune to fire, but all bosses aside from Dry Bowser can be defeated using fire. Otherwise, they act as they do in previous games, and their appearance returns to their Super Mario Bros. appearance, but with a red, yellow and white flower with eyes. Blocks containing Super Mushrooms or Fire Flowers are much more common than in previous games. Mario can still only shoot two fireballs at once.
Super Mario Galaxy
In the Wii game Super Mario Galaxy, when Mario or Luigi obtains this item, he will go into his fire form allowing him to throw fireballs, defeat enemies and light torches. Unlike other games where the powerup lasts until the player takes damage, the powerup only lasts 20 seconds, although Mario can still take damage with this form, but the Fire Flower will not wear off. (The time isn't discovered until the second game, in the box burning missions.) Also unlike the other games, the way Mario or Luigi uses it is by simply shaking the Wii Remote. These flowers first appeared in Freezeflame Galaxy along with its counterpart, the Ice Flower. They also appear in the Dusty Dune Galaxy, Deep Dark Galaxy and Snow Cap Galaxy.
New Super Mario Bros. Wii
They also appear in New Super Mario Bros. Wii having the same effect as its predecessor. If a fireball is thrown at a character in a bubble, the character's bubble will pop. Fireballs thrown can also get eaten by Yoshi and spit out as projectiles.
A similar item called the Ice Flower appears. They have nearly the same effect, except the ice balls thrown are slower, break when coming in contact with the floor, and freeze enemies, rather than defeating them.
Super Mario Galaxy 2
The Fire Flower reappears in Super Mario Galaxy 2. Nothing has changed about the Fire Flower from the previous game, and it therefore has the same function as it did in Super Mario Galaxy. Making its debut appearance is a new minigame called Crate Burning, which appears in only two missions in the entire game: "The Great Crate Incinerator" in the Rightside Down Galaxy and "Burning Upside Dizzy" in the Upside Dizzy Galaxy. In this minigame, the player is presented with numerous breakable crates, all of which need to be burned within a short time limit via the use of a Fire Flower in order to earn the Power Star for the missions. Also, they appear while fighting Squizzard in the Slipsand Galaxy's first and third mission.
Super Mario 3D Land
New Super Mario Bros. 2
The Fire Flower reappears in New Super Mario Bros. 2. It has the same behavior as in the previous 2D Mario games. They are also used to shoot fireballs in pipes that release coins and items such as a Mega Mushroom, three 1-Up Mushrooms, or a Star.
New Super Mario Bros. U
The Fire Flower reappears in New Super Mario Bros. U and behaves like in the previous 2D Mario games.
Super Mario 3D World
The Fire Flower reappears in Super Mario 3D World, and behaves like it did in Super Mario 3D Land.
Mario is Missing!
The Fire Flower is absent from the NES and SNES versions of Mario is Missing!. However, it does appear in the PC version. They will appear after Luigi has returned all artifacts in each city. He can then use Fire Flower to burn the Koopaling and make it to the next floor of Bowser's Castle.
Super Mario Land 2: 6 Golden Coins
Replaced with Flowers in Super Mario Land, Fire Flowers appear for Super Mario Land 2: 6 Golden Coins with the same design as in Super Mario World. While the Fire Flower acts in the same way as any other title, Mario's fire form in this game has a feather on top of his hat instead of changing the color of his clothes; this is most likely due to the lack of colors on a Game Boy. Wario also uses a Fire Flower to become Fire Wario during the third portion of the final boss battle.
Fire Flowers also appeared in the cartoon television series The Super Mario Bros. Super Show!, The Adventures of Super Mario Bros. 3, and Super Mario World. When Mario or Luigi touch one, they gain their fire powers as normal, although most episodes have their fire costumes either be not changed at all, an orange hat and shirt with red overalls, or the normal red overall/white hat. In Super Mario World, Fire Flowers look like orange roses that are always connected to a ? block and sometimes spit out fireballs themselves. In The Adventures of Super Mario Bros. 3 episode "Reign Storm", the Robot Princess orders all Fire Flowers to be extinguished, as if they were actual fires.
The Club Nintendo comic "Super Mario: Verloren in der Zeit" reveals that Fire Flowers have existed since the Stone Age. In this story, Mario uses a Fire Flower to throw Fireballs at a Tyrannosaurus Rex.
In a similar manner to how Mario and Luigi have both eaten and "absorbed" Mushrooms throughout their games, there is much controversy over whether Mario must eat a Fire Flower or simply touch it to become Fire Mario. Although most games make Fire Flowers simply disappear upon contact with Mario, this comic shows that Mario does indeed eat Fire Flowers to use their powers. Mario even reveals something about their taste, claiming that Fire Flowers "taste disgusting, but if I eat them, I can shoot Fireballs".
Super Smash Bros. series
In the Super Smash Bros. series, the Fire Flower has appeared as an item in every installment. Once picked up, the player can shoot a continuous but short stream of fire from it to damage anyone nearby. It does have a limit to how much fire it can use, and will lose its abilities after constant use. The Fire Flower also deals fire damage if it hits an opponent when thrown. In Super Smash Bros., the Fire Flowers are alike to their debut appearance. In Super Smash Bros. Melee, they look like actual flowers with eyes and white petals, like Power Flowers. In Super Smash Bros. Brawl and Super Smash Bros. for Nintendo 3DS / Wii U, the Fire Flower is given its current appearance.
Mario and Luigi use Fireballs as their standard special move. Mario shoots red fireballs, and Luigi shoots green. This is the first game in which Mario and Luigi use the flower itself to throw fireballs rather than transforming into their Fire forms, a tactic that would later be used in the Paper Mario and Mario and Luigi series.
Mario Kart series
Within all the Mario Kart games, the Fire Flower most commonly appears as the emblem of the Flower Cup. Below are more notable examples of the appearance of the Fire Flower.
Mario Kart Wii
Mario Kart 7
In Mario Kart 7, the Fire Flower makes its first appearance as a usable item that can be obtained from an Item Box. Using it, a racer can throw several Fireballs forward or backward to make racers spin out and drop coins when hit. The Fire Flower will last for ten seconds after it's used or when the player uses ten fireballs. Fireballs can be thrown with this item by pressing the button.
Mario Kart 8
The Fire Flower item returns in Mario Kart 8, and it works the same as it did in Mario Kart 7.
Paper Mario series
During the Paper Mario series, the player can use these items towards the enemies Mario and his partners encountered during their travels. If used against ice enemies, it will deal an extra 2 damage points, whereas it will replenish the health of fire enemies such as the Lava Bubble and Ember. These items can be purchased in many shops, such as in the Shroom Grocery from Toad Town, Koopa's Shop from Koopa Village, and Yoshi's Cabana from Lavalava Island from the Nintendo 64 game Paper Mario.
Paper Mario: The Thousand-Year Door
Also in the Nintendo GameCube game Paper Mario: The Thousand-Year Door, they can be purchased in Toad Bros. Bazaar from Rogueport, Niff T.'s Shop from Petalburg, and Keelhaul Key Galleria from Keelhaul Key. They are (sort of) replaced by Fire Bursts in the sequel. If used against ice-type enemies, it will deal an extra damage point. Fire Flowers can be also used as ingredients to be made into new items with a help of Tayce T. or Zess T. Recipes can be found below.
Like in the Club Nintendo comic mentioned above, this game seemingly confirms that Mario does indeed eat Fire Flowers: a certain optional scene in the Glitz Pit has Mario informing a Lakitu cameraman that he "shoots fire when he eats a flower".
Super Paper Mario
In Super Paper Mario, Fire Flowers appear in the skies of Lineland and at Fort Francis, in the room on the left, thus giving them cameos as non-collectible items. Fire Bursts apparently replaced the Fire Flowers from the previous Paper Mario games. The Fire Flower uses the Super Mario World appearance for these games.
Paper Mario: Sticker Star
The Fire Flower returns as a sticker in Paper Mario: Sticker Star, having its appearance from New Super Mario Bros. and onward. Using it in battle turns Mario into Fire Mario, allowing him to throw fireballs at any ground and low-altitude enemies, causing them to disintegrate into ash if their HP is fully depleted. There also exist two other variants of this sticker: the Shiny Fire Flower and the Flashy Fire Flower, which inflict more damage. Fire Flowers also appear on the Battle Spinner; lining up three has the same effect as a Fire Flower sticker.
Mario & Luigi series
Mario & Luigi: Superstar Saga
Mario & Luigi: Partners in Time
In the Nintendo DS game Mario & Luigi: Partners in Time, Fire Flowers are referred to as Bros. Flowers. If used, the player attacks all the enemies with a certain amount of fireballs by constantly pressing the button if the big fireball is passed on to Mario or the button if it is passed on to Luigi. The player can also attack flying enemies by pressing the button (if passed to Mario) or the button (if passed to Luigi), making their baby counterparts shoot fireballs. In addition, the damage may burn their foes. There are three related items in the game: the Mix Flower, Ice Flower, and Copy Flower.
Mario & Luigi: Bowser's Inside Story
Fire Flowers again appear in Mario & Luigi: Bowser's Inside Story as a Special attack obtained by collecting all ten Pump Works Attack Pieces. They're used almost exactly the same as Bros. Flowers in Partners in Time, but after certain number of hits, player can hit both and buttons to attack simultaneously. Using this item will also change Mario's and Luigi's outfits to Fire Mario and Fire Luigi's outfits. The move costs 4 SP (3 with a Budget Charm or Thrift Charm, 2 with a Tight Belt). Rapid button mashing is required to get an Excellent rating on this attack.
Mario & Luigi: Dream Team
The Fire Flower returns as Luigi's second available Bros. Attack in Mario & Luigi: Dream Team, costing 5 BP. Its Attack Pieces are found in Dozing Sands. This attack can hit any enemy on the ground, and airborne enemy, and may inflict burns. Damage is inflicted after the attack ends, and thus it is impossible for enemies to be defeated during the attack.
When used, Mario and Luigi enter their fire forms and begin charging and hurling fireballs at the enemies erratically. The player must press or for Mario and Luigi respectively to launch fireballs randomly at the enemies, fully charged fireballs (that flash to signal this) doing the most damage. If the fireballs are fired prematurely, they will do considerably less damage and none at all if the fireballs are charged too long. If all fireballs are thrown appropriately, Mario and Luigi will eventually start charging fireballs rapidly, the player having to mash and in order to throw as many as possible at the enemies.
The greater the amount of fireballs thrown, the better the ranking the player receives in the aftermath of the attack, ranging from "OK!" to "Excellent!" ratings. The damage dealt from this attack is given a Fire attribute, and thus deals critical damage to Caccacs and Beehoss.
Use the A and B Buttons for the bros. When the fireballs get big, throw 'em! If you throw all big fireballs, it's bonfire time! Mash the A and B Buttons!
Mario vs. Donkey Kong 2: March of the MinisMario vs. Donkey Kong 2: March of the Minis, when a Mini Mario touches a Fire Flower, he becomes a Fire Mini Mario and begins throwing fireballs within a limited time to knock out enemies or defeat them. These items can be obtained from a ? Block during those levels.
Mario Golf: World Tour
In Mario Golf: World Tour, Fire Flowers appear as usable item shots. In addition to increasing shot distance, they also allow the ball to burn through obstructions such as trees. It is the signature item for Princess Daisy.
Puzzle & Dragons: Super Mario Bros. Edition
In Puzzle & Dragons: Super Mario Bros. Edition, Fire Flowers are used in the place of the Fire Element tiles.
Appearances in other games
In all four Animal Crossing games, a Fire Flower is available as a furniture item. In most games the Fire Flower resembles its original Super Mario Bros. incarnation, with later games using 8-bit stylized graphics, though in Animal Crossing: New Leaf the Fire Flower, along with all other Mario based items, are given their current appearances.
In Terraria, there is an item called the "Flower of Fire". The item is a wand which most resembles the Super Mario World Fire Flower in appearance. Using it shoots a fireball that bounces across the ground.
Super Smash Bros. series Trophies
Super Smash Bros. Melee
Super Smash Bros. Brawl
Super Smash Bros. for Nintendo 3DS / Wii U
Names in other languages
Mario & Luigi: Partners in Time
Mario & Luigi: Bowser's Inside Story