dryad arbor ruling can it tap when played?

[hideseek]

I know you can not tap creatures the first turn you play them because they have summoning sickness unless they have haste

I also know you can tap lands the first turn you play it because I play forest and immediately tap it for mana turn 1

but what about land-creature dryad arbor which of rules apply to it, the rules for creature or the rules for land?

[Kenji]

Because it is a creature, it will suffer from summoning sickness and be unable to tap for its mana ability.

302.6. A creature’s activated ability with the tap symbol or the untap symbol in its activation cost can’t
be activated unless the creature has been under its controller’s control continuously since his or her
most recent turn began. A creature can’t attack unless it has been under its controller’s control
continuously since his or her most recent turn began. This rule is informally called the “summoning
sickness” rule.

You'll note that the rule doesn't account for a creature having one or more other card types. This is because that doesn't matter. If your creature is also a land, artifact, and/or enchantment, for example, it'll still be unable to attack or use its activated abilities with the tap/untap symbol unless it has been under your control continuously since your most recent turn began.

...Wait, why are we having this discussion again? Dryad Arbor's reminder text even answers this for you:

(Dryad Arbor isn't a spell, it's affected by summoning sickness, and it has "{T}: Add {G} to your mana pool.")

Yes, yes, reminder text doesn't count as rules text and doesn't have any effect on play -- but it's certainly correct here.

Edit - Further clarification can be found within the Gatherer rulings for various land cards. For example, this is from the rulings for Raging Ravine:

A land that becomes a creature may be affected by "summoning sickness." You can't attack with it or use any of its {T} abilities (including its mana abilities) unless it began your most recent turn on the battlefield under your control. Note that summoning sickness cares about when that permanent came under your control, not when it became a creature.