The Western Zodiac and Chinese astrology are, by no means, the only astrological systems that exist, or which have existed throughout time. Many other cultures also have, or had, a zodiacal system. In Celtic lore, for example, there is a 13-"sign" zodiac that, at first glance, may appear to bear some organizational similarity to the Western Zodiac. However, it is quite distinct both in structure and focus.
Unlike the Western Zodiac and Chinese astrology, the Celtic Zodiac reflects the importance and reverence the Celtic culture had for nature, particularly trees. Each of the 13 signs is represented principally by a tree or other plant important in Celtic myth and lore. Here are the 12 signs of the Celtic Zodiac:
December 24 - January 20: The Birch
2. January 21 - February 17: The Rowan
3. February 18 - March 17: The Ash
4. March 18 - April 14: The Alder
5. April 15 - May 12: The Willow
6. May 13 - June 9: The Hawthorn
7. June 10 - July 7: The Oak
8. July 8 - August 4: The Holly
9. August 5 - September 1: The Hazel
10. September 2 - September 29: The Vine
11. September 30 - October 27: The Ivy
12. October 28 - November 24: The Reed
13. November 25 - December 3: The Elder
If you are interested in Celtic mythology or the Celtic Zodiac in particular, I strongly recommend that you visit The Celtic Zodiac, the site where I obtained these incredible images. Incidentally, these images are the original creations of Margaret Walty found in "The Celtic Lunar Zodiac," authored by Helena Patterson. You will find a wealth of information about Celtic astrology and folklore at this site, including more detailed descriptions of the characteristics the Celts attributed to people born under these "signs."