• Ultraviolet Photography

Geranium robertianum [Herb-Robert]

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#1 nfoto

    Former Fierce Bear of the North

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Posted 20 December 2012 - 14:10

Rørslett, B. 2012. Geranium robertianum L. (Geraniaceae). Herb-Robert. Flowers photographed in visible and ultraviolet light. http://www.ultraviol...um-herb-robert/

Geranium robertianum L.

NO: Stankstorkenebb; Urakatt; Urdakatt
SE: Stinknäva
DK: Stinkende Storkenæb
FI: Haisukurjenpolvi
DE: Stinkender Storchschnabel
EN: Herb-Robert

This is a small perennial species widely distributed in Europe and introduced to North America. It occurs in a diversified range of habitats from seashores to deeply shaded forest floors, mainly in the lowlands and the overall distribution is southern. Flowering is less frequent when it grows in a shady location, though. The distinct, unpleasant smell makes it an easily identfiable species in the field. The growing season can be very long and it is not uncommon to find it flowering late in the autumn up to the first snow falls.

This specimen was photographed near Oslo, Norway, 5. Nov 2007.

Attached Image: GERA_ROB_I0711050083_VIS.jpg
Image reference: GERA_ROB_I0711050083_VIS.jpg
Visible light: Nikon D40, UV-Nikkor 105 mm f/4.5 lens, Baader UV/IR Cut filter.

Attached Image: GERA_ROB_I0711055939_UV.jpg
Image reference: GERA_ROB_I0711055939_UV.jpg
Ultraviolet light: Nikon D200, UV-Nikkor 105 mm f/4.5 lens, Baader U 2" (Venus) filter, SB-140 flash.

Compared to other Geranium species, the corolla of G. robertianum is only moderately reflective in UV. The veins of the petals are prominent in UV though and patches of larger conical cells are seen too. Also frequently observed in UV is petal damage done by rain or visiting insects. The sampled specimen shows signs of a fungal infection on the left petal (necrotic tissue in which sporangia are seen). The infected area is virtually undetactable on the visible-light record and stands clearly out on the UV picture.

[Published: 24 Dec 2012. Last updated 17 Jan 2013]