Mono-Green in the Woods follows these rules:
Deck Construction
Constructed decks must contain a minimum of 60 cards (no maximum deck size; however, you must be able to shuffle your deck with no assistance). With the exception of basic land cards (Plains, Island, Swamp, Mountain, Forest), a player’s combined deck and sideboard may not contain more than 4 of any individual card, counted by its English card title equivalent.
There are no sideboards in Mono-Green in the Woods.
Your deck may only contain colorless and mono-green cards originally printed in Alpha, Beta, Arabian Nights, Antiquities, Legends, The Dark, and Fallen Empires.
Here's a Scryfall search link that shows you all of the legal cards: https://scryfall.com/search?q=legal%3Aoldschool+color%3C%3DG
There are no restricted or banned cards in Mono-Green in the Woods, unless you are not playing for ante (then the ante cards are banned, of course). Yes, that means you can play 4 Black Lotus, if you really want. And yes, you can play Elves of Deep Shadow.
Reprints with original frame and original art are fine, e.g. your Chronicles Ernham Djinn is fine, but your 7th Edition Untamed Wilds is not.
Gameplay
Matches of Mono-Green in the Woods usually consist of only a single game. You must play unsleeved, without a playmat, on an unclean and/or rough surface. Watch out for that sap on that tree stump!
If you and your opponent do not both agree to play for ante, both players should remove all of the ante cards from their decks and replace them with other legal cards. After doing so, both players must still present a legal deck, according to the deck construction rules listed above.
Errata for Chaos Orb
Chaos Orb
{2}
Artifact
{1}, Tap: Choose a nontoken permanent on the battlefield. If Chaos Orb is on the battlefield, flip Chaos Orb onto the battlefield from a height of at least one foot. If Chaos Orb turns over completely at least 360 degrees during the flip, and lands resting on the chosen permanent, destroy that permanent. Then destroy Chaos Orb.
Note: because of how Chaos Orb is worded, with it being destroyed after a flip, it can still be Disenchanted or Shattered in response to the activation, which will nullify the ability to flip, since it is no longer on the battlefield. This is consistent with the wording of Chaos Orb not being sacrificed upon activation, as it probably would with modern templating. Also note that Chaos Orb chooses, but does not target.
Errata for Ring of Ma'rûf
Ring of Ma’rûf
{5}
Artifact
{5}, Tap, Exile Ring of Ma’rûf: The next time you would draw a card this turn, instead choose a colorless or mono-green card you own from outside the game, and put it into your hand.
Note: this maybe be used to get any colorless or mono-green card you own from outside the game that would otherwise be legal for the game in which Ring of Ma’rûf is activated. You can get your 5th Black Lotus, but you can't get an ante card during a non-ante game or any other card that is illegal according to the deck building rules listed above.