Three Sisters
The three sisters garden is a traditional Native American guild for growing staple crops. Consisting of maize, beans, and squash, the three sisters were first domesticated and cleverly combined in Mesoamerica, before spreading north.
In a three sisters garden, maize provides a living structure for the beans to climb. The beans, in turn, put nitrogen into the soil that the other plants use. Squash spreads along the ground, keeping the soil moist and blocking weeds from growing.
#Specialization
A community that specializes in relationship with the three sisters will invariably tend strongly towards horticulture, and therefore live in settled villages. These communities will practice slash-and-burn agriculture, growing different guilds of plants at different stages and moving around the jungle in a regular cycle. The three sisters are the first guild in the cycle.
#Variations
Some communities add a fourth sister, most commonly to attract pollinating insects. West of the Rocky Mountains, Rocky Mountain bee plant serves as this fourth sister; East of the Rockies, amaranth.