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Luronium natans [Floating Water-plantain]

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#1 nfoto

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Posted 18 January 2013 - 23:10

Rørslett, B. 2013. Luronium natans (L.) Raf. (Alismataceae). Floating Water-plantain. Flowers photographed in visible and light. http://www.ultraviol...water-plantain/

Luronium natans (L.)Raf.
Syn.: Elisma natans L.
NO: Flytegro
SE: Flytsvalting
DK: Vandranke
DE: Froschkraut
EN: Floating Water-plantain

A small perennial aquatic macrophyte endemic to western and central Europe, L. natans is considered endangered and the populations are declining.

It can occur in a wide range of localities, but may find its optimum habitat in small peat-stained lakes and ponds. As so often the case for aquatic plants, L. natans can occur in a number of growth forms, often with submerged rosettes comprised of narrow strap-shaped leaves. Floating leaves arise from the basal rosettes, or are borne on trailing floating stems with flowers. Vegetative organs (winter buds, turions) form late in the season and are importants agents for dispersal. Flowering commences in early summer (late June to early July and usually lasts only for a few weeks. Although the flowers, borne single on short scapes, are emerging into air, they are vulnerable to rapid variations in water level and frequently are seen drowned. Thus, in many sites seedset suffers badly.

Plants often remain sterile in several consecutive seasons. Slender, sterile specimens of Alisma plantago-aquatica occasionally have been misidentified as L. natans and in fact, all recent Scandinavian finds of alleged L.natans have been based upon wrong identification of vegetative material. In Norway, only four sites are currently known and all are small forest lakes clustered in a small area north of Oslo. The species is on the National Red List and protected by Law.

Plants photographed 29 Jun 2010.

Attached Image: LURO_NAT_B1006296293_VIS.jpg
Image reference: LURO_NAT_B1006296293_VIS.jpg
Habitat overview showing flowering plants and well developed floating leaves. Nikon D3S, Voigtländer APO-Lanthar 125 mm f/2.5 lens.

Attached Image: LURO_NAT_I1006291619_VIS.jpg
Image reference: LURO_NAT_I1006291619_VIS.jpg
Visible light. Nikon D3S, Voigtländer APO-Lanthar 125 mm f/2.5 lens.

Attached Image: LURO_NAT_I1006290862_UV.jpg
Image reference: LURO_NAT_I1006290862_UV.jpg
Ultraviolet light. Nikon D40X, UV-Nikkor 105 mm f/4.5 lens, Baader U2" (Venus) filter, daylight + SB-140 flash.

The petals of L. natans show a darker UV mark at the base, but it is noteworthy this mark is smaller than the yellow one seen in visible light. The veins are more prominent in UV and are lined with conical cells. Patches of conical cells are present towards the edges and apex of the petals.

[Published: 19 Jan 2013]

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