Like Tracts, most Graduals show clear signs of centonization, a process of composition in which an extended vocabulary of stock musical phrases are woven together. Some phrases are only used for incipits, some only for cadences, and some only in the middle of a musical line. The Gregorian Graduals can be organized into musical families that share common musical phrases. Although nearly half of the Gregorian Graduals belong to a family of related chants in the fifth mode, the most famous family of Graduals are those of the second mode, commonly called the "Iustus ut palma" group after one representative chant. The Graduals of the Old Roman chant fall similarly into centonization families, including a family corresponding to the "Iustus ut palma" group.