Eremophila mackinlayi [Desert Pride]

[Andrea B.]

Blum, A.G. (2013) Eremophila mackinlayi F. von Mueller (Scrophulariaceae) Desert Pride. Flowers photographed in visible, ultraviolet and infrared light. http://www.ultraviol...ila-mackinlayi/

 

Death Valley National Park, Furnace Creek Ranch, Furnace Creek, California, USA

29 February 2012

Wildflower

 

Synonyms:

• Bontia mackinlayi (F.Muell.) Kuntze
  
• Pholidia mackinlayi (F.Muell.) Baill. ex Wettst.
  

Comment:

This lovely Australian native was found growing in a small xeriscaped garden by a swimming pool at the Furnace Creek Ranch lodging in Death Valley National Park (USA). That location initially mislead me to an erroneous identification of the plant as some kind of Leucophyllum because I though the garden must contain all local or regional native plants given the presence of numerous Enceila farinosa specimens and other US natives. However, our member Dave Oldfield pointed out that my supposed Leucophyllum looked very much like his E. hygrophana seen here: http://www.ultraviol...ila-hygrophana/. After a crash course in Eremophila identification with the help of Dave and his wife Sue, who grows Eremophilas, I finally figured out that I had photographed an Eremophila mackinlayi.

 

The key difference between E. mackinlayi and E. hygrophana is the absence or presence, respectively, of glandular hairs on the leaves and branches. Bjørn Rørslett kindly examined his photographs of the same purple-flowered, silvery-leaved plant and could find no glandular hairs - nor could I spot any in my own photographs. And so the ID was made. Subsequent prowling around the internet showed that Australian native plants are very popular in arid areas of California and Arizona and various Eremophila species are sold in plant nurseries there. And so the implausibility of finding an Eremophila in the US was easily explained too.

 

In UV light the wooly white throat hairs of E. mackinlayi are preserved as UV-white against the uniformly UV-dark corolla. The would appear to act as landing lights on the platform lip for any pollinating insects having UV vision. The flower is unremarkable in Infrared light, all parts being uniformly IR-reflective.

 

Reference:

1. Chinnock, R.J. (2007) Eremophila and Allied Genera: A Monograph of the Myoporaceae. Rosenberg Publishing, Sydney. http://keybase.rbg.v...acketedkey/1541

 

Equipment [Nikon D300-broadband + Nikon 105mm f/4.5 UV-Nikkor]

 

Visible Light [f/8 for 1/250" @ ISO 200 with Nikon D3S]

 

Visible Light [f/8 for 1/250" @ ISO 200 with Nikon D3S]

Although not the best close-up, it seems apparent that there are no glandular hairs on the sepals and leaves of this specimen.

 

Visible Light [100% crop from original of preceding photo]

 

Visible Light [f/11 1/500" @ ISO 400 in Sunlight with Baader UVIR-Block Filter]

 

Ultraviolet Light [f/11 for 1/250" @ ISO 800 with SB-14 UV-modified Flash and Baader UV-Pass Filter]

 

Infrared Light [f/11 for 1/1000" @ ISO 800 in Sunlight with B+W 092 IR-Pass Filter]

[nfoto]

The first close-up of the corolla shows an abundance of stellate hairs on the outside. These were very visible in UV when I shot the same specimens later. Also seen on foliage in combination with single hairs in a tomentose layer.

[Andrea B.]

I should mention that when working the Eremophila key,

I ruled out E. stronglyophylla based on leaf shape and presence of glandular hairs in that species.

 

The following key step for leaf characteristics is reached:

• Leaves linear to oblanceolate --> E. hygrophana or E. mackinlayi
  
• Leaves ovate/obovate, spathulate or orbicular --> E. stronglyophylla, E. hygrophana or E. mackinlayi
  

As my specimen above clearly had oblanceolate leaves, I picked the 1st step.

Even had I stretched the matter and declared my leaves as possibly ovate/spathulate to follow the 2nd key step,

the later key step for presence/absence of glandular hairs would have once again led me to E. mackinlayi.