Orbexilum stipulatum, commonly known as largestipule leather-root or Falls-of-the-Ohio scurfpea, was a flowering plant that was endemic to Rock Island in the Falls of the Ohio; an area of rapids and rocky limestone outcrops in Kentucky's portion of the Ohio River.

Although all searches to rediscover Orbexilum stipulatum have thus far been unsuccessful, two other species strongly associated with buffalo that were once thought to be extinct, Trifolium stoloniferum and Solidago shortii, have been rediscovered on old buffalo trails and a mineral lick.

However, Orbexilum stipulatum differs in that in the 20 years it was monitored by botanists, it was never once observed to produce seed.

[3] The Orbexilum Stipulatum is still considered an enigma as it has confused many botanists with its exact species type.

His traditional assignment inspected the inflorescence, basis of foliage, and flower structure, which found similarities between these two species.