Submitted by György Chityil ... on Sat, 01/20/2018 - 01:20 Hierarchy: NounDescription: {{rfv-sense}} A small air canal in horsetails' stems lined with primary phloem and xylem.Ngram: vallecularNgram Text: vallecularSource: WiktionaryIssue: 0Wiktionary tag: rfv-senseNgram Count: 1