Liber
Liber is an ancient Italic deity of germination and agriculture. Later he was assimilated with Bacchus, Greek Dionysus. Their names were used interchangably. Liber Pater [he was always called 'Liber Pater' Venerable] was an important deity. In Lavinium an entire month was given to his celebration which featured a procession of a phallus that was crowned by the most worthy of the matronae.
Additionaly his cult was to assure the the success of the crops and to avert evil; the phallus was a fascinatio of the fields much like Priapus was in the courtyards of homes to avert danger. For his protection of the wheat and fruits Liber always remained a deity of the plebeians.
In Rome, his temple, the temple of Ceres, Liber and Libera on the Aventine, was built in 493 B.C.E. by the consul Sp. Cassius, after the dictator A. Postumius vowed it, due to a famine, if the gods would bring abundance. This was the Greek cult and thus an official recognition of Greek Dionysus. Though Bacchus in his Greek form had long been worshipped in Italy. The 'thiasos' Latin: thiasus was usually male or mixed with the female sacerdos presiding and were devoted to banquets and retelling of the god's myth.
Bacchus was worshipped in the Roman way with collegia devoted to celebrating his feria with dinners much in the manner indicated by Ovid in his Fasti.
The Liberalia an ancient festival supposedly even more ancient than the Cerealia was given to enjoyment while priests and priestesses of Liber sold small cakes, liba in honour of the festival. Also during this festival young males exchanged the toga praetexta of childhood for the toga virilis or toga libera.
Sources & Literature: Bruhl, "Liber Pater" Anne-Francoise Jaccottet "Choisir Dionysos" Susan Guettel Cole,various articles Ovid, Fasti