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UltravioletPhotography

Hieracium scabrum [Rough Hawkweed]


Andrea B.

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Blum, A. G. (2015) Hieracium scabrum Michx. (Asteraceae) Rough Hawkweed. Flowers photographed in ultraviolet and visible light. http://www.ultraviol...rough-hawkweed/

 

Southwest Food Mart, Southwest Harbor, Maine, USA

The flower was found in a weedy patch next to the parking lot of this grocery store.

09 July 2014

14 July 2014

Wildflower

 

Synonyms:

  • Sticky Hawkweed
  • Hieracium scabrum Michx. var. scabrum
  • Hieracium scabrum Michx. var. tonsum Fernald & H.St.John
  • Hieracium scabrum var. intonsum Fernald & H. St. John
  • H. scabrum var. leucocaule Fernald & H. St. John
  • H. scabrum var. tonsum Fernald & H. St. John

Comment:

The Hieracium are notoriously difficult to identify. Still on occasion one does find examples which fit the type well. In particular the leaf shape, the presence of abundant stipitate glands on the involucre and branched hairs on stems seen in these photos are characteristic of H. scrabrum.

 

Reference:

1. New England Wild Flower Society (2014) Hieracium scabrum Michx. Rough Hawkweed. https://gobotany.new...racium/scabrum/

 

Equipment [Nikon D600-broadband + Carl Zeiss 60mm f/4.0 UV-Planar]

Unless otherwise noted.

 

Visible Light [f/9 for 1/250" @ ISO-160 with Nikon Df + Nikon 60mm f/2.8G Micro-Nikkor]

An inflorescence of H. scabrum.

hieraciumScabrum_070814swFoodMartSwhME_5441pn.jpg

 

Visible Light [f/9 for 1/500" @ ISO-400 with Nikon Df + Nikon 60mm f/2.8G Micro-Nikkor]

Foliage of H. scabrum.

hieraciumScabrum_070814swFoodMartSwhME_5490pn.jpg

 

Visible Light [f/10 for 1/1600" @ ISO-400 with Nikon Df + Nikon 60mm f/2.8G Micro-Nikkor]

Cypselae of H. scabrum. The ribs form a small ring at the apex.

hieraciumScabrumCypsela_071114swFoodMartSwhME_5896pn.jpg

 

Visible Light [f/14 for 1/15" @ ISO-800 with Nikon Df + Nikon 60mm f/2.8G Micro-Nikkor]

Stem of H. scabrum showing branched hairs.

hieraciumScabrumStems_071214swFoodMartSwhME_6080pn.jpg

 

Visible Light [f/11 for 1.3" @ ISO-200 with onboard Flash and Baader UVIR-Block Filter]

Glandular hairs on involcre of H. scabrum.

hieraciumScabrumInvolucreVisFlash_070914swFoodMartSwhME_20096pn.jpg

 

Ultraviolet Light [f/11 for 15" @ ISO-400 with SB-14 UV-modified Flash and Baader UV-Pass Filter]

Glandular hairs on involcre of H. scabrum. A long exposure was taken in order to fire the UV flash twice for more even lighting.

hieraciumScabrumInvolucreUVBaadSB14_070914swFoodMartSwhME_20105pn.jpg

 

Visible Light [f/11 for 1/5" @ ISO-400 with onboard Flash and Baader UVIR-Block Filter]

Capitula of H. scabrum.

hieraciumScrabrumVisFlash_071414swFoodMartSwhME_21927pn.jpg

 

Ultraviolet Light [f/11 for 20" @ ISO-400 with SB-14 UV-modified Flash and Baader UV-Pass Filter]

Capitula of H. scabrum. A long exposure was taken in order to fire the UV flash three times for more even lighting.

hieraciumScrabrumUVBaadSB14_071414swFoodMartSwhME_21923pn2.jpg

 

Ultraviolet Light [f/11 for 20" @ ISO-400 with SB-14 UV-modified Flash and Baader UV-Pass Filter]

Abaxial view of capitula of H. scabrum. A long exposure was taken in order to fire the UV flash twice for more even lighting.

hieraciumScrabrumAbaxialUVBaadSB14_071414swFoodMartSwhME_21949pn.jpg

 

Ultraviolet Light [f/11 for 20" @ ISO-400 with SB-14 UV-modified Flash and Baader UV-Pass Filter]

Capitula of H. scabrum. This flower head was somewhat the worse for wear. A long exposure was taken in order to fire the UV flash three times for more even lighting.

hieraciumScabrumUVBaadSB14_070914swFoodMartSwhME_20090pn.jpg

 

 

FNA | Family List | FNA Vol. 19, 20 and 21 | Asteraceae | Hieracium

18. Hieracium scabrum Michaux, Fl. Bor.-Amer. 2: 86. 1803.

Plants: (15–)30–60+ cm.

Stems: proximally piloso-hirsute (hairs 1.5–5+ mm), sometimes stellate-pubescent as well, distally stellate-pubescent, sometimes stipitate-glandular, rarely piloso-hirsute (hairs 1–2+ mm).

Leaves: basal 0(–3), cauline 6–24+; blades elliptic or oblanceolate to spatulate or lanceolate, (20–)35–80(–120+) × (10–)20–35(–50+) mm, lengths 2–6+ times widths, bases cuneate to rounded-truncate, margins usually entire, sometimes denticulate, apices rounded to obtuse, faces hirtellous to piloso-hirsute (hairs 0.5–1+ mm).

Heads: (5–)10–25(–50+) in corymbiform to paniculiform arrays.

Peduncles: stellate-pubescent and stipitate-glandular (hairs 0.3–0.6+ mm).

Calyculi: bractlets 12–15+.

Involucres: campanulate, 7–9 mm.

Phyllaries: 13–21+, apices ± acuminate, abaxial faces stellate-pubescent and stipitate-glandular, rarely, if ever, piloso-hirsute.

Florets: (30–)40–60+; corollas yellow, 9–11 mm.

Cypselae: columnar, 2.5–3 mm; pappi of 30–40+, stramineous bristles in ± 2 series, 6–7 mm.

Flowering: Jul–Sep. Sandy soils, open, disturbed sites (fields, stream sides), wooded sites; 10–300+ m;

N.B., N.S., Ont., P.E.I., Que.; Ark., Conn., Del., D.C., Ga., Ill., Ind., Iowa, Ky., Maine, Md., Mass., Mich., Minn., Mo., N.H., N.J., N.Y., N.C., Ohio, Okla., Pa., R.I., S.C., Tenn., Vt., Va., W.Va., Wis.

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I think you said that last year, too. :D

 

It helps that on Mount Desert Island there have been a lot of surveys and lists published over the years. So at least we can rule out some possibilities before beginning the agony of Hieracium identification. I have quite a few Hieracium-like flowers which remain unidentified or which can only be labeled with genus, but not species.

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