Lectionary 1637, or ℓ 1637 in the Gregory-Aland numbering, is a Greek manuscript of the New Testament on parchment leaves, dated paleographically to the 9th century.[1]
It is written in Greek Uncial letters on 144 leaves (30 by 26 cm), 2 columns per page. The codex contains some Lessons from the four Gospels lectionary (Evangelistarium). The manuscript contains several library inserts. It is a palimpsest. The upper text is written in a minuscule hand.
It was described by Kenneth Willis Clark.
The codex now is located in the University of Michigan (MS. 37) in Ann Arbor.[1]