3,039. Plants of One Species That Look Different

Hilchos Kilayim 2:17

The agents of the court came back on chol hamoed Pesach to check on late-ripening crops. If mixed species sprouted, there is no delay. Rather, agents of the court would go right out and declare the whole field ownerless if 1/24 of the crop was from a mixed species.

Hilchos Kilayim 3:1

Some species of plants may diversify into different forms based on differences in where they grow, how the soil is treated, etc., with the result that they end up looking like two different species. However, since they are actually of one species, they do not present a problem of kilayim with one other.