Pelargonium tongaense [Tonga Pelargonium]

[nfoto]

Rørslett, B. 2022. Pelargonium tongaense Vorster. Geraniaceae. Tonga Pelargonium. South-African flowers photographed in ultraviolet (UV) and visible light. LINK

 

The species name indicates the province of Tongaland in KwaZuluNatal in South Africa.

 

A small perennial herb, Pelargonium tongaense was described as a new species as late as in 1983 (Vorster & van der Walt 1983).

The authors describe it as a species of shaded woodland on iron-rich soils, in a local climate with moist warm summers and cold winters.

 

This species is endemic to KwaZuluNatal, on the eastern side of the continent. Its distribution map is below (from

http://www.ville-ge.ch/musinfo/bd/cjb/africa/details.php?langue=an&id=10593),

 

 

 

I photographed this species in Kirstenbosch National Botanical Garden at Cape Town.

 

In visible light, the bright orange-red flowers are prominent,

 

 

The appearance seen in ultraviolet (UV) is rather dull false-colour blue, with some traces of darker patches towards the flower centre, and on the basal parts of the upper petals,

 

 

All photographs on this page are copyright Birna Rørslett and may not be used without explicit permission from the author.

 

 

Literature:

 

Vorster, P. & van der Walt, J.J.A. 1983. Two new species of Pelargonium L' Herit. (Geraniaceae) from South Africa. S.Afr. J. Bot. 2:76-81

 

[Published 12 February, 2022]

 

[Andrea B.]

Birna, what camera/lens combo were you using? Just curious.

[nfoto]

Visible: Nikon Df, 125mm f/2.5 APO-Lanthar

 

UV: Nikon 3200 (built-in Baader-U), UV-Nikkor 105mm f/4.5, SB-140 flash

[colinbm]

The petals seem to be asymmetrical, the three bottom are different to the top two, both in visible light & UVA.

[nfoto]

The zygomorphic flower is a key feature of the genus Pelargonium and differentiate it from the close relative Geranium, the latter having actinomorphic (like spokes in a wheel, radially symmetric) flowers.

[ulf]

https://www.britannica.com/science/zygomorphic-flower

[LookCloser]

Here is a different Perlagonium species I shot a little while back.  The zygomorphic arrangement of the flower is even more pronounced in this species.

https://www.ultravioletphotography.com/content/index.php?/topic/4809-lechenaultia-macrantha/&do=findComment&comment=49454

 

[nfoto]

Interesting, I have the same Pelargonium capitatum (from SA) on my to-do list for publication. Had to take a break to get other pile(s) of unfinished work a respite, however.

[LookCloser]

I will be interested to see if your P. capitatum from South Africa has the same floral signature as the one I shot.  I believe that the species has been naturalised in Western Australia for some time.  With a potentially small founding population and some drift over time I wonder if it will be comparable.

[nfoto]

I hear you, so published P. capitatum right now. The UV appearance is largely similar, given that the flowers were in a different (and earlier) stage of development than your specimen.