Viperaria (Scorzonera hispanica)
Caption: Hippolyte Coste - Flore descriptive et illustrée de la France, de la Corse et des contrées limitrophes, 1901-1906 - This image is in public domain because its copyright has expired.

Viperaria (Scorzonera hispanica)
Caption: Picture modified from Bley, Franz - Botanisches Bilderbuch (1897/98) - Permission granted to use under GFDL by Kurt Stueber. Source: www.biolib.de - Permission is granted to copy, distribute and/or modify this image under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled GNU Free Documentation License.

Viperaria (Scorzonera hispanica)
Caption: C. Hoffmann - Botanischer Bilder-Atlas (1884) - This image is in the public domain because its copyright has expired.

Viperaria (Scorzonera hispanica)
Caption: Photo by Leo Michels. Usage: Public Domain