<i>Caltha palustris</i> seeds, legitimately copied from USDA website
USDA, NRCS. 2016. The PLANTS Database (<a rel="nofollow" class="external free" href="https://plants.usda.gov">http://plants.usda.gov</a>, 13 February 2016). National Plant Data Team, Greensboro, NC 27401-4901 USA.
2016-02-13
<a rel="nofollow" class="external free" href="https://plants.usda.gov/gallery/pubs/capa5_003_php.jpg">http://plants.usda.gov/gallery/pubs/capa5_003_php.jpg</a>