The
rostral scale is as deep as broad or broader than deep. The upper head-scales are small, smooth, imbricate;
supraocular scale narrow, rarely broken up. The
internasals are contact or separated by one or two scales. There are 8 to 13 scales on a line between the
supraoculars; usually one or two, rarely three, series of scales between the
suboculars and the
labials; 9 to 12
upper labials, second usually forming the anterior border of the
loreal pit, third largest;
temporal scales smooth. The dorsal scales are more or less distinctly keeled, in 21 (rarely 19 or 23) rows;
ventrals 145–175;
anal scale entire;
subcaudals in two rows 53–76. The upper parts are usually bright green, rarely yellowish, greyish, or purplish brown, with or without black, brown, or reddish spots; usually a light, white, yellow, or red streak along the outer row of scales; end of tail frequently yellow or red; lower parts green, yellow, or whitish. ==Taxonomy and common names==