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Sagittaria sagittifolia [Arrowhead]


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#1 nfoto

    Former Fierce Bear of the North

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Posted 06 February 2013 - 14:36

Rørslett, B. 2013. Sagittaria sagittifolia L. (Alismataceae). Arrowhead. Flowers photographed in visible and ultraviolet light. http://www.ultraviol...olia-arrowhead/

Sagittaria sagittifolia L.
NO: Pilblad
SE: Pilblad
DK: Pilblad
FI: Pystykeiholehti
DE: Gewöhnliches Pfeilkraut
EN: Arrowhead

An aquatic plant with a wide European and Asian distribution, S. sagittifolia can occur entirely submersed , with floating leaves, or emerging from the water. Flowering is mainly seen for the latter stage of development. This plant thrives on fertile mud soils in slow-flowing rivers, ponds, and lakes, mainly with a eutrophic character. It is replaced by the related S. trifolia L. and similar species in North America. Like other members of this genus, S. sagittifolia is very characteristic and can easily be identified from a distance by its habitus. It hybridises with the northern S. natans and this hybrid is fairly common in northern parts of Sweden and Finland; it also has been documented from Norway.

The inflorescence opens from below and the showy white dioecious flowers change from male to female stages as flowering progresses. The flowering usually is in mid summer. The white petals carry a prominent red mark at their basal portion. Smaller insects are frequently seen visiting S. sagittifolia flowers, but I haven't seen bees, bumblebees, or butterflies paying them much attention.

Specimens collected and photographed at Lillestrøm, Norway, 6 Jul 2008.

Attached Image: SAGI_SFO_A08070679372_VIS.jpg
Image reference: SAGI_SFO_A08070679372_VIS.jpg
Visible light. NIKON D200, Coastal Optics 60 mm f/4 APO lens, Baader UV/IR Cut filter, daylight.

Attached Image: SAGI_SFO_A08070679522_UV.jpg
Image reference: SAGI_SFO_A08070679522_UV.jpg
Ultraviolet light. NIKON D200, Coastal Optics 60 mm f/4 APO lens, Baader U 2" (Venus) filter, SB-140 flash.

Patches rich with conical cells make the petal a variegated greyish shimmering.

[Published 6 Feb 2013]