"The Kew Plant Glossary (2nd ed., with some additions)" by Beentje (2020)
- Like a string of beads, cylindrical and constricted at regular intervals, nearly the same as torulose, but that is slightly more irregular or slightly flattened.
- Beentje, H. 2020. The Kew Plant Glossary: An Illustrated Dictionary of Plant Terms, Second Edition, reprinted with some additions. -xii + 184 pp. Royal Botanic Gardens, Kew, Richmond.