Abstract

Euphorbia costatalata is allied to Euphorbia tortilis but differs in having prominent ribbing and up to 5 wings, segments longer, thinner, not spiral, cymes fewer per axil, trapezoidal glands that are humped convexly upwards, flattened ovaries with non-connate styles, capsules concave on top, and seeds dark brown with light speckles and streaks. This species appears to replace E. tortilis north of the Nilgiri and Bilirangan hill ranges.