title: The fine structure of fossil plant cell walls.
abstract: The cell walls of sieve elements in the primary phloem of the Carboniferous fern Tubicaulis contain structural features that morphologically resemble cellulose microfibrils in extant plants. This may be the oldest example of distinct fibrillar structures in the fossil record. The possible identity and significance of these features are discussed and their structure is compared with that of cell walls in other fossil and extant plants.
authors.forename: E L
authors.initials: EL
authors.lastname: Smoot
authors.forename: T N
authors.initials: TN
authors.lastname: Taylor