Ranunculus muricatus [Spinyfruit Buttercup]

[igoriginal]

Butorsky, I. (2014) Ranunculus muricatus L. (Ranunculaceae) Spinyfruit Buttercup. Flowers photographed in ultraviolet and visible light. http://www.ultraviol...ruit-buttercup/

 

Brandon, Mississippi, USA (Google map: http://goo.gl/maps/PGByh)

24 March 2014

17:35 Central Standard Time

Wildflower

 

Synonyms:

• Spinyfruit Buttercup
  
• Rough-Seed Buttercup^[1]
  

Comment:

Although R. muracitus is originally native to the Eurasian continent (including some of the outlying islands and peninsulas located off of the main landmass), it has managed to spread itself to other continents and is thus an alien and / or introduced species ... including (but not limited to) Southwestern Australia^[2], various parts of Africa, and has been confirmed to populate certain states within the United States. These known host states (as of the time of this publication, 2014) are Alabama, Arkansas, California, Florida, Georgia, Hawaii, Louisiana, Mississippi, Oregon, South Carolina, Texas and Washington^[3], although it is not beyond the possibility that the species will continue to spread to other adjacent localities (much like many other members of the Ranunculus genus.)

 

R. muricatus particularly thrives near water bodies and/or soggy locations, such as along river banks, swamps, irrigation ditches, poorly-drained soils, flood plains, storm drains, and frequently rainy micro-climates. Although it can do quite well in full sun (provided that there are sufficient periods of drenching rain in between the sunny days), it generally thrives in partial shade, where there is greater potential for soil to retain much needed moisture even during extended drier periods. Thus, dried-out soils and predominantly low-humidity/arid regions will likely lead to the demise of this species, in particular. On the other extreme, however, it will also not take well to harshly frigid regions, whereas cool/lukewarm and wet winters seem to be the optimal blend of weather conditions to facilitate hearty growth and flowering in the spring.

 

Since there are virtually hundreds of Ranunculus species (some of which may have even evaded classification or discovery, thus far), is it most vital to find physical cues which help to better identify the precise species in question. Thankfully, R. muricatus provides such a good clue (its characteristic "spiny fruit"), which can be found on the ends of stems where the flowering period has passed and the petals have dropped off to reveal a seed-bearing fruit (technically referred to as an achene^[4]) that is quite jagged, sharp to the touch, and riddled with many tiny, thorn-like "spines" (thus, the inspiration behind the common naming scheme of this species).

 

(See the associated third and forth photos, within this publication, showing a good example of these identifying features.)

 

UV-A Appearance:

When custom-white-balanced against PTFE ("virgin-white Teflon"), 3/4 of the petals' length (from the outside in) of R. muricatus generally appear to maintain their yellow-dominant color (albeit, under certain shooting conditions - such as late-afternoon sun - there may be a slightly "golden" coloration, giving the petals a yellow-orange appearance compared to the solid yellow/yellow-green observed in the visible bandwidth), while the remaining 1/4 of the inner-most petal parts - as well as the entire center of the flower (like the majority of its Ranunculaceae family brethren) - evidently exhibit a UV-dark/absorptive scheme (black).

 

References:

1. Plants for a Future http://www.pfaf.org/...culus+muricatus

2. Florabase http://florabase.dpa...se/profile/2933

3. Plants Database of the USDA http://plants.usda.g...le?symbol=RAMU2

4. Britannica http://www.britannic...pic/3507/achene

 

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- Camera: Panasonic Lumix G5 (full-spectrum converted)

 

- Lens: Super Lentar 35mm F/3.5 (Kyoei / Kuribayashi 35mm F/3.5 optical variant; 46mm filter thread, 23mm front element diameter, 11.5mm rear element diameter, M42-mount adapter over T-mount base, Serial # 37200), mounted on additional macro-extending helicoid tube (an M42-to-Micro 4/3 adapter with a macro extension-capable helicoid design).

 

- Settings for visible exposure: ISO 160, Aperture F/11, Shutter 1/160 sec, S8612 (2mm thick) filter, white balance set to in-camera default "flash" scheme, color-cast corrected in post-photo editing.

 

- Settings for UV-A exposure: ISO 160, Aperture F/11, Shutter 5 sec, U-340 (2mm thick) and S8612 (2mm thick) filter stack, in-camera CWB (custom-white-balance) set to PTFE (virgin-white polytetrafluoroethylene / Teflon).

 

NOTE: Identification of R. muricatus, due to "spiny" fruit characteristics, as seen in below in a quick camera-phone snapshot.

 

Higher-magnification photograph of a single fruit (achene) of R. muricatus (Spinyfruit Buttercup) better reveals the many tiny little spine-like "thorns" which protrude from each individual seed component. This is essential, for the proper identification of this species.

 

The entire fruit part, as seen here, is just 10 millimeters across, about the diameter of an average human adult pinkie fingernail.

[nfoto]

I surmise the slightly darker patches (seen in the Vis picture) are oil-containing cells as seen in other Ranunculus flowers? interestingly there seem to be a concordance between this area and what shows up UV dark. From other species of the buttercup family, we already know these oily areas of the honey leaves are rendered dark in IR. Very few floral structures show a similar behaviour in IR, only the bracts of dandelions come to mind.

[igoriginal]

I surmise the slightly darker patches (seen in the Vis picture) are oil-containing cells as seen in other Ranunculus flowers? interestingly there seem to be a concordance between this area and what shows up UV dark. From other species of the buttercup family, we already know these oily areas of the honey leaves are rendered dark in IR. Very few floral structures show a similar behaviour in IR, only the bracts of dandelions come to mind.

 

That is fascinating, isn't it?

 

It makes me wonder if this is some extended evolutionary advantage of some sort, since the "patterns" have evolved to express themselves in IR, as well as UV.

 

What do we know about any animals which may have a higher IR-sensing ability, compared to human vision? Perhaps some plants have evolved to attract foraging / grazing animals, to improve the spread of their seeds. Particularly ruminants? (Cattle, buffalo, deer, goat, sheep, llama, pronghorn, antelope, etc). That is to say that as a ruminant grazes / forages through the grass, it inadvertently dislodges the seeds from these plants, which better helps to propagate them and ensure the species' ongoing survival.

 

So, the question we need to ask is: Do some foraging / grazing mammals perceive any IR wavelengths? (Unlike humans). And if so, this may infer that perhaps the Ranunculus genus (and any other flowering genus like it) has extended its attraction of beneficiary animals beyond just pollinating insects and birds.

 

Questions to consider and explore, I think.

[Andrea B.]

I need to list the format for online references. We need to see a title and date of accession. so I'll try to get to that this evening.