Home / Anomalous_Items / Aquatic_Macrophytes / Emergent_Leaves / Ranunculus
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Name derivation:
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‘Little frog’ – diminutive of Rana = frog (L.).
Common names include ‘aquatic buttercup’, ‘water crowfoot’.
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Classification:
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Ranunculus Linnaeus; approximately 600 species descriptions are currently accepted
taxonomically, including terrestrial as well as aquatic habitats (Subclades
Batrachium ‘aquatics’ and Hecatonia ‘semiaquatics’); aquatic species are considered to be
derived from terrestrial ancestors, as reviewed by Hörandl and Emadzade in
their ‘pluralistic approach for classification’ that includes analysis of both
molecular and morphological traits(2012).
Order Ranunculales; Family Ranunculaceae
Herbaceous dicot, includes many
hybrids; ~40% of Ranunculus species
are polyploids (Ibid.).
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Morphology:
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Heterophylly includes
highly dissected submerged leaves 2 – 3 cm long, and more entire 3-5 lobed
floating and emergent leaves. Leaf anatomical and morphological development
includes temperature and submersion in water, and likely involves growth
hormones (Bostrack and Millington 1962).
the latter, especially the importance of ethylene and its precursor 1-aminocyclopropane-1-carboxylic
acid (ACC) has been confirmed and is reviewed by Samarakoon and Horton
(1984). The authors experiments
demonstrate increases in leaf petiole leaf with higher levels of ethylene in
the range 0.01 to 1000 ml l-1 within one day.
Such elongation can keep leaves emergent with rising water level.
Flowers are 5-part and either yellow or white (species specific).
Fruits are achenes (dry with one seed).
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Similar
genera:
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Anenome and Isopyrum are treated as outgroups (Hörandl
and Emadzade 2012.).
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Habitat:
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Freshwater, shallow
marshes, streams and lakes. Provides
food for ducks but is poisonous to many mammals until plants are dried.
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References:
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Bostrack,
J.M. and W.F. Millington 1962. On the determination of leaf form in an aquatic
heterophyllous species of Ranunculus. Bulletin of the Torrey Botanical Club
89(1):1-20.
Hörandl,
E, and K. Emadzade 2012. Evolutionary classification: A case study on the diverse plant genus Ranunculus L. (Ranunculaceae). Perspectives in Plant Ecology, Evolution
and Systematics 14:301-324.
Samarakoon, A.B., and R.F.
Horton 1984. Petiole growth in Ranunculus sceleratus L.:
Ethylene synthesis and submergence.
Annals of Botany 54:263-270.
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