The invention relates to a coil (2) of cutting wire for a vegetation cutting machine, wherein the wire (20) is coiled on itself about an axis so as to form at least two temporarily bonded turns (21) and a central void (22), characterized in that the surface of the wire portion forming the innermost turn of the coil facing the central void (22) comprises a plurality of grooves (230) creating a succession of protrusions and recesses extending parallel to said axis. The invention also relates to a cutting assembly for a vegetation cutting machine such as a border trimmer or a brush cutter, said assembly including at least one coil (2) according to one of claims 1 to 9 and a cutting head (1) comprising: a body (10) defining an inner recess for the coil (2) and provided with a peripheral opening (12a, 12b) for the emergence of a length of cutting wire separated from the coil, and capable of being driven in rotation by a motor, and a central mandrel (13) for supporting said at least one coil, said mandrel comprising at least one arrangement (135") adapted to cooperate with the grooves (230) of the coil so as to ensure rotational engagement between the mandrel and the coil, the mandrel being able to selectively rotate relative to the body.L'invention concerne une bobine (2) de fil de coupe pour une machine de coupe de végétation, dans laquelle le fil (20) est enroulé sur lui-même autour d'un axe de manière à former au moins deux tours (21) liés temporairement et un vide central (22), caractérisée en ce que la surface de la partie du fil formant le tour le plus interne de la bobine faisant face au vide central (22) comprend plusieurs rainures (230), créant une succession de saillies et d'évidements s'étendant parallèlement audit axe. L'invention concerne également un ensemble de coupe pour une machine de coupe de végétation, par exemple un coupe-bordure ou une débroussailleuse, ledit ensemble comprenant au moins une bobine (2) selon l'une des revendications 1 à 9 et une têt
