1) Leafstalk sheath 2) Plant sheath 3) Plant-stem sheath 4) Sheaf of a leafstalk 5) Sheath of a leafstalk 6) Stem covering 7) Zoological sheath 
• (n.) See Ochrea.
(pl. ocreae) a sheath around the stem derived from the leaf stipules, primarily used in the Polygonaceae
A membranous sheath at nodes of the stem in the Polygonaceae, formed by fusion of the stipules. (pl. ocreae)
a stipular, tube-shaped sheath that surrounds the stem just above the leaf base; a characteristic of the smartweed family (Polygonaceae).
A metal or boiled leather greave, or piece of leg armour, protecting the lower leg. On Thracians this armour also covered the knee. 
O'cre·a noun [ Latin ] See Ochrea . 
A boot-shaped or tubular stipule, as in Polygonum.
In botany, an ocrea or ochrea is a cup-shaped structure, formed from the united stipules or leaf bases, that sheathes the stems of certain plants.