A Dragon card is a card with the creature type Dragon in its type line. Similarly, a creature on the battlefield is a Dragon if it has the Dragon creature type. A card that has "Dragon" in the name (such as Temple of the Dragon Queen) isn't a Dragon card unless it also has the Dragon creature type.
As this land enters, you may reveal a Dragon card from your hand. This land enters tapped unless you revealed a Dragon card this way or you control a Dragon.
: Add one mana of the chosen color.