Rubus flagellaris [Northern Dewberry]

[igoriginal]

Butorsky, I. (2014) Rubus flagellaris Willd (Rosaceae) Northern Dewberry. Flowers photographed in ultraviolet and visible light. http://www.ultraviol...thern-dewberry/

 

Brandon, Mississippi, USA

Google map: http://goo.gl/maps/PGByh

30 March 2014

16:43 Central Standard Time

Wildflower

 

Synonyms:

• Northern Dewberry
  
• Common Dewberry^[1]
  

Comment:

R. flagellaris is native to the North American continent, and has been found to inhabit many of the states of the eastern half of the USA, as well as some Canadian provinces^[2].

 

Thus, R. flagellaris is quite hardy with its adaptability and resilience to growing in many variable soil conditions and climates. Like the many other wild "blackberries" and "raspberries" within the same genus of Rubus which it bares a very close relation to, the perennial "northern dewberry" produces a dark, inky-purple, edible "fruit" (technically, referred to as an aggregate fruit or composite drupe^[3], composed of a cluster of individual "drupelets") that is semi-sweet and tart in taste, and is an excellent choice for canning or used in the making of preserves and jams.

 

Because of the fact that the Rubus genus contains hundreds of flowering low-growing vines and shrubs, of which some can appear nearly indistinguishable (including the very similar-looking flowers and drupes which they produce), it is most vital to find physical cues which may help to improve one's chances of a successful identification of the precise species in question - in this case, R. flagellaris.

 

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

 

UV-A Appearance:

When custom-white-balanced against PTFE ("virgin-white Teflon"), the petals of R. flagellaris are rendered in a dark indigo-purple color (although there is suggestive evidence of some increased UV-brightness/reflectivity toward the center of the flower, as seen in the associated photo, marked by a "whitish" inner petal region), while the filaments atop which the stamens sit (like the majority of its Rubus genus brethren) - evidently exhibit a UV-dark/absorptive scheme (black). Also, the stamens themselves now appear in a light-indigo/purplish coloration, in contrast to their typical dark-tan or copper-brownish coloration under a visible-spectrum exposure.

 

References:

1. Wildflowers of Illinois in Savannas & Thickets http://www.illinoisw...cm_dewberry.htm

2. Plants Database of the USDA https://plants.usda....ile?symbol=RUFL

3. Britannica http://www.britannic...ic/172140/drupe

4. The Biota of North America Program http://www.bonap.org...2010/Rubus.html

 

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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 800, Aperture F/11, Shutter 1/320 sec, S8612 (2mm thick) filter, in-camera CWB (custom-white-balance) set to 18% neutral gray target, color-cast further corrected in post-photo editing.

 

- Settings for UV-A exposure: ISO 800, Aperture F/11, Shutter 3 sec, U-340 (2mm thick) and S8612 (2mm thick) filter stack, in-camera CWB (custom-white-balance) set to PTFE (virgin-white polytetrafluoroethylene / Teflon).

 

 

 

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Identification suggestions:

Unlike some other members of the Rubus genus, R. flagellaris exhibits especially dramatic physical changes that occur between its juvenile (younger) and more matured stages of life.

 

In particular, young stems (including the central/ primary stem of the plant) are typically very tender and bright green, covered with a thick arrangement of hair-like prickles that are soft to the touch. On the other hand, the central stems of mature plants appear brownish-green/olive in color, take on a more "woody" and less pliable consistency (not unlike some thin tree branches), and have shed a good portion of their soft, hair-like prickles to gave way to hardened, sharp, thorn-like prickles, instead.

 

These very striking changes in the plant's physiology and appearance are not very common to some of the other Rubus genus members, and so, can be used (along with other accompanying data, such as regional distribution maps of specific species^[4], as well as plant-part/anatomy measurement listings) to improve one's chances of a positive identification (through the process of elimination).

 

See the two associated photo samples below, as a visual comparison.