Colonization refers the process of mushroom mycelium consolidating its hold on a substrate by extending new strands of mycelium into nutritious material. Typically, rhizomorphic growth will ensue from a healthy mycelium, which further consolidates the mycelium's hold on the substratum. The other type of growth, more wispy in nature is tomentose growth, which means 'of or like matted hair'. It can be just as good or better than rhizomorphic growth, depending on genetics. Certainly one or the other can be isolated on an Agar plate from a multi-spore syringe.