Coluber ordinatus Linnaeus, 1766
Coluber taenia Schoepf, 1788
Coluber ibibe Daudin, 1803
Tropidonotus bipunctatus Schlegel, 1837
Tropidonotus jauresi Duméril, Bibron, and Duméril, 1854
Eutaenia sirtalis obscura Cope in Yarrow, 1875
Eutaenia sirtalis melanota Higley, 1889
Eutaenia sirtalis graminea Cope, 1889
| The primary basis for recognizing different subspecies is the dorsal coloration pattern, which varies geographically. In T. s. sirtalis, the dorsal color is usually brown, gray, or black. The medial or vertebral stripe is fairly distinct and ranges from white to yellow to tan, with much individual variation. This stripe often includes just under half of each paravertebral row of scales (in addition to the scale rows directly aligned with the vertebral column). There are 19 dorsal scale rows in all, and this number may reduce to 17 near the anus. The lateral stripe covers rows 2 and 3 and is also yellowish. Between the medial and lateral stripes may be a double row of black spots, which may fuse together either horizontally or vertically (this feature is also highly variable).|
There is a brown ventrolateral stripe that extends only slightly onto the ventrals, if at all. The venter is green or yellow tinted. The anal plate is undivided. Males have a simple hemipenis with an unbranched sulcus spermaticus, five large spines at the base, and many tiny recurved spines in oblique rows on the shaft (left, c).
Some color variations in the Eastern garter snake. Left and center pictures from Rossman et al. (1996), Plate 12.
Right picture from Ernst and Barbour (1989), color plates not numbered.