Plant Systematics and Evolution

, Volume 176, Issue 3–4, pp 179–203

Laminar hydathodes inUrticaceae: Survey of tribes and anatomical observations onPilea pumila andUrtica dioica

  • N. R. Lersten
  • J. D. Curtis


Laminar hydathodes are known from only three dicot families. InUrticaceae they are associated with minor vein junctions in all five tribes, as surveyed from cleared leaves of 43 species in 30 genera. Only one species lacked hydathodes. Exclusively adaxial hydathodes were found in 28 genera. In tribeElatostemeae, laminar hydathodes inPilea andPellionia species are abaxial, adaxial, or on both surfaces. Guttation was observed in four species.Urtica dioica (adaxial) andPilea pumila (abaxial) were studied anatomically in detail. Hydathodes in the former have normal bundle structure but xylem gaps sometimes occur. In the latter, phloem is displaced in three previously undescribed ways: 1) ends abruptly near hydathode, 2) curves into connecting vein at adjacent junction, or 3) departs xylem, skirts hydathode independently, and rejoins adjacent xylem strand. Laminar hydathodes are a unifying character of theUrticaceae, and they also strengthen its close relationship to theMoraceae.

Key words

Angiosperms dicotyledons Urticaceae Pilea pumila Urtica dioica Guttation hydathodes leaf anatomy 


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Copyright information

© Springer-Verlag 1991

Authors and Affiliations

  • N. R. Lersten
    • 1
  • J. D. Curtis
    • 2
  1. 1.Department of BotanyIowa State UniversityAmesUSA
  2. 2.Department of BiologyUniversity of WisconsinStevens PointUSA

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