noun
or och·rea ˈäkrēə, ˈōk-
( plural ocre·ae or ochre·ae -ēˌē)
Etymology: New Latin, from Latin ocrea greave, legging; perhaps akin to Latin ocris stony mountain — more at mediocre
: a tubular sheath around the base of the petiole consisting of a single stipule in the red clover or of a pair of coherent stipules in the buckwheat family (Polygonaceae)