There are ten 7th-level druid spells in AD&D, up from eight in OD&D. All eight spells from OD&D have made the transition to AD&D. Chariot of Sustarre is a new spell, and finger of death has been bumped up from 6th level.
Animate Rock: The caster can animate up to 2 cubic feet of stone per caster level, and it will follow simple orders of about 12 words or so. The only other restriction is that the stone must be a whole object in itself; you can't animate part of a boulder, for example. There are no stats given for combat and the like, but animate object is referenced, so presumably the guidelines there would be used.
The OD&D version of the spell had one major difference, in that the stone being animated had a 30% chance to not obey the caster. This is a pretty big deal, considering that it's a 7th-level spell; for that investment, you'd expect it to work reliably. The AD&D spell specifically states that the stone being animated is mindless, so something fundamental has changed about the spell since then. Perhaps in the OD&D version the spell was infusing the stone with an elemental spirit of some sort? The druids may have grown frustrated with the spell not working all the time, and altered it to move the stone without the need for dealing with elementals.
The animated stone was also given a movement rate (2-4", more for statues), which isn't done in AD&D. The duration was a flat 6 turns, whereas in AD&D it's 1 round per level.
Chariot of Sustarre: This spell creates a flaming chariot, and a pair of fiery horses to pull it. It can carry up to eight passengers as decided by the caster, and anyone else within 5 feet of it will take damage as from a wall of fire. The chariot and steeds can only be damaged by magical weapons or water. The big thing here is that this is the first mention of Sustarre in D&D. The spell is named after B. Dennis Sustare, the creator of the druid class. As for who Sustarre is in the World of Greyhawk, I can't find anything outside of this spell. Unless something comes up to contradict it later, I'll make him the very first Great Druid.
Confusion: Causes 2-8 creatures within the area of effect to become confused, and act randomly. Actions for confused creatures are checked at the start of each round, with the following results: wander away for 1 turn, stand confused for 1 round, attack nearest creature for 1 round, or attack druid and allies for 1 round. That first option will pretty much take an enemy out for the entire battle, as it lasts for ten rounds. Affected creatures get a saving throw each round with a -2 penalty, but I'm not sure if it throws off the spell completely or simply allows that creature to act normally for 1 round. I would go with the latter. The spell can affect more creatures than the dice indicate, dependent on the druid's level compared to that of the strongest creature affected.
The OD&D spell was automatically effective against creatures of less than 2 HD. It also had a weird delayed effect, where the caster rolled 1d12, subtracted his level, and the result was the number of rounds that the spell was delayed. The spell does clarify that the saving throw is to act normally for 1 round, as I suspected. The "wander away for 1 turn" result wasn't present, the range was 12" as opposed to 8", and the duration was fixed rather than based on caster level. Presumably in-world the spell was altered to get rid of the delay effect, at the cost of automatically affecting weaker creatures.
Conjure Earth Elemental: Summons a 16 HD earth elemental that does the druid's bidding completely, and remains until destroyed, dismissed or sent away by the druid (or the spell ends). The OD&D spell was much the same, although it did have a restriction whereby only one elemental could be summoned per day.
Control Weather: A more powerful version of the cleric spell. It has twice the duration and area of effect, and the weather conditions can be altered by two steps instead of one if greater mistletoe is used.
The OD&D version of the spell was much different, in that it had a set number of effects it could create, and wasn't dependent on the current weather conditions. It was probably a more versatile and powerful spell, but perhaps druids stopped using it because it was harming the weather patterns.
Creeping Doom: This spell summons 500-1,000 venomous arachnids, insects and myriapods, which swarm forth in a 2"x2" mass at a speed of 1" per round. Anything caught within the area that is subject to normal attacks will be killed instantly, as each creature inflicts 1 point of damage and then dies. (Presumably anything with over 1,000 hp would survive, but that's well beyond AD&D's power scale.) If the mass gets further than 8" away from the caster, it loses 50 of its number for each 1". I've always loved this spell, if only for its rad name.
In OD&D the number of creatures summoned was 100-1,000, with a 1-3 turn delay until they appeared. It seems as though the OD&D version of the spell could only be targeted at one creature, which would be pursued by the creeping doom until destroyed or the spell ended; the AD&D spell could also be interpreted in the same way. Most importantly, OD&D gives no indication of what happens to those caught by the spell, which is a pretty big oversight.
Finger of Death: The caster points his finger, and the target's heart stops. It doesn't get much simpler than that. In OD&D, the spell had the restriction that it could be used by druids "only when their lives are in the direst peril". Moral standards have lapsed since then, it seems. The spell now has a range of 6", whereas in OD&D it was 12".
Fire Storm: Fills a 2" cubic area per caster level with flames that deal 2d8 damage to all within (+1 per level of the caster). The area can be shaped by the druid. It can also be reversed as fire quench, which douses normal fire in an area double that of a fire storm (magical fires have a 5% chance per caster level of being doused).
The OD&D spell was almost exactly the same; it had a larger area of effect, but dealt less damage (2d6).
Reincarnate: If cast on a creature that has been dead for no longer than a week, it brings them back in a new body. What the creature is reincarnated as is determined by a random roll, and the vast majority of the results are animals; there is literally only a 21% chance that someone will come back as a PC race, and no chance at all for dwarves, halflings and half-orcs to retain their original race. Even the character's class might be different, although there are no rules for determining this; it just says that the "character must be created", which to me indicates that while stats are rolled randomly and race is determined by the spell, the player can choose their own class just as they would when creating any other character. To be honest, casting this spell on a fellow player is the ultimate dick move. I would think that most players would prefer to wait for a raise dead or resurrection.
The OD&D version of the spell simply said that it was the same as the magic-user spell, but with a bias towards animals; no other guidelines were given.
Transmute Metal to Wood: Changes metal items to wood, with a maximum weight of 80gp per caster level. Magic items only have a 10% chance of being affected. Once an item is changed, it can never be changed back, not even with a dispel magic.
The OD&D spell had a shorter range, and could only change a weight of 50gp per level.
And that's it for druid spells! I realise that this stretch of the blog hasn't been the most exciting. I do have a tendency to get bogged down in minutiae, but once I'm through the magic-user and illusionist lists it will be a while before I'll be stuck doing this sort of thing again. Until then, I'll try to keep on a regular schedule and finish the Player's Handbook as quickly as I can. Hey, it took me five years to get through the Monster Manual, this is very fast by comparison.