Myrsine linearifolia is a branched shrub that grows between 2.5 and 8 meters tall. The branches are green to reddish brown, ascending, slender, and glabrous. The leaves are simple, alternate, well-distributed on the upper branches, or somewhat clustered toward the ends. The blades are linear, measuring 5–9 cm in length and 0.25–0.4 cm in width. The apex is falcate, long-attenuate, and usually slightly hooked, while the base is attenuate. The surfaces are glabrous except for the margins, which are sparsely ciliate toward the base and may have minute rectangular glandular hairs on the upper surfaces near the base. The leaves are inconspicuously punctate, often yellowish purple toward the base, and slightly fleshy. The margins are entire and slightly revolute. The midrib is prominent, though venation is otherwise obscure. The petioles are flattened, winged, and 1–2 mm long. Stipules are absent. The flowers are arranged in bracteolate fascicles of 1–3 among the leaves, with pedicels measuring 1–4.2 mm long, glabrous to sparsely puberulent. The flowers appear to be bisexual (perfect). The calyx consists of 4–5(6) lobes, usually deeply divided, imbricate or valvate in bud, punctate, or with secretory lines. The lobes are approximately 0.5–1 mm long, glabrous, with ciliate margins. The corolla consists of 4–5(6) greenish petals; the lobes are nearly distinct or connate up to half their length, imbricate in bud, oblanceolate, and about 2.2–2.5 mm long, with ciliate margins. The anthers measure 1.6–1.8 mm long, with a glabrous apex or a few hairs. The ovary is superior, 3–5(6)-carpellate, and 1-celled, with few ovules in a single row. In staminate flowers, the ovary is reduced, sterile, or absent. The style is short or absent, terminal, and the stigma is capitate-angled. The fruit is a black drupe at maturity, ellipsoid, and approximately 6 mm long. Each fruit contains a single small, dark-colored, subglobose seed excavated at the base. It is found in diverse mesic to wet forests between 580-1,280 meters.