Each season: a weather card resolves, everyone gains Energy (3 + tree Sugar), then players take turns — one action each, going around — until all pass. Then upkeep, then the next season. The start player passes left each season. Eight seasons total.
Metabolize (free, up to 3 Carbon → Energy per season) fuels your actions.
Actions: Extend into an adjacent hex (cost = its Resistance). Decompose a tile you sit on for a nutrient (a spent tile keeps its type, so groves survive). Symbiose with an adjacent tree for steady Sugar. Fruit on a tile (caps a tip, scores, enables spores). Sporulate to jump within 3 hexes. Antibiosis to remove a bordering rival. Adapt to buy a trait.
Upkeep: 1 Energy per branch tip, but your first 2 tips are free. Unpaid tips die.
Scoring: fruiting bodies, grove majorities (3+ connected same-nutrient tiles, most fruiting bodies wins), trees, network reach, trait sets, spread, and leftover nutrients.