title: Endoplasmic reticulum aggregates of ordered structure.
abstract: Membranous bodies with a quasi-crystalline arrangement are present in Acer stem phloem. They only occur in developing sieve elements and are formed by the association of originally randomly arranged endoplasmic reticulum cisternae.
authors.affiliation: Department of Biochemistry, University of Cambridge, UK.
authors.forename: F B
authors.initials: FB
authors.lastname: Wooding