Plantarum indigenarum et exoticarum icones ad vivum coloratae, oder, Sammlung nach der Natur gemalter Abbildungen inn- und ausländlischer Pflanzen, für Liebhaber und Beflissene der Botanik /.
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biodiversitylibrary.org/page/44261197
The British ferns, or, Coloured figures and descriptions with the needful analyses of the fructification and venation of the ferns of Great Britain and Ireland
London :Lovell Reeve,1861.
biodiversitylibrary.org/page/51658732
Ectypa plantarum ratisbonensium :
Regensburg :Verfertiget und verlegt von Johann Mayr ... und gedruckt mit Zeitlerischen Schriften,1787-1793.
biodiversitylibrary.org/page/59792728
Smithsonian Institution, Richard A. Howard Photograph Collection
USDA PLANTS images
Howard, R.A. Provided by Smithsonian Institution, Richard A. Howard Photograph Collection. United States, Florida, Miami-Dade Co., Miami, Fairchild Tropical Botanic Garden.
Description: Polypodium hesperium, west of AZ Hwy. 89A in Sterling Canyon, a tributary of Oak Creek Canyon, 35.0244 -111.7429, Coconino County, Arizona, 11 Apr 2014. Date: 11 April 2014, 14:12. Source: Polypodium hesperium. Author: Patrick Alexander from Las Cruces, NM.
Description: Polypodium hesperium, west of AZ Hwy. 89A in Sterling Canyon, a tributary of Oak Creek Canyon, 35.0244 -111.7429, Coconino County, Arizona, 11 Apr 2014. Date: 11 April 2014, 14:16. Source: Polypodium hesperium. Author: Patrick Alexander from Las Cruces, NM.
Description: English: Botanical specimen in the Regional Parks Botanic Garden, Berkeley, California, USA. Date: 14 November 2013, 18:22:45. Source: Own work. Author: Daderot.