Joachim Camerarius (1534-1598) published four books of emblems about the natural world (plants-animals-birds-reptiles), with each emblem accompanied by a Latin distich along with an essay in Latin. Later, these four books were then collected into a single volume, Symbolorum et Emblematum Centuriae Quatuor (1668), which you can find at GoogleBooks. To find the single volume, with much higher quality page scans, visit the University of Munich Digital Library. There is a beautiful edition online at the Internet Archive, too. In the widget, the emblems identified as coming from Books 1, 2, 3, or 4 are from Camerius.
The widget emblems identified as Book 5 are not by Camerarius but by Bornitius. Inspired by the design of the Camerarius books, Bornitius, a.k.a. Jakob Bornitz (ca. 1560-1625), published a single "century" of emblems under the title Symbola et Emblemata, which is available at GoogleBooks; as the subtitle of the book explains: continuatio famosi Ioachimi Camerarii intitulari potest. You can find a different edition, with the emblems neatly outlined in the letters of the motto text, at the University of Mannheim CAMENA project. There is also a wonderful online edition as part of the Emblem collection at the Herzog August Bibliothek.
Meanwhile, here is a section of the title page from one of the volumes of Camerarius's emblems, Volume 1 - dedicated to plants:
Here is the Camerarius Emblem of the Day; you can see a vocabulary list and notes by visiting the latest Camerarius posts at this blog. Meanwhile, you can also get a copy of the widget for your own website or blog if you want! Ready for more? Check out the Random Camerarius Emblem too! :-)