Schiedea hookeri is a sprawling perennial herb that becomes woody toward the base. The stems are often swollen at the nodes, terete (cylindrical), 4-angled or ridged, measuring 3–10 dm long, and are multi-stemmed from the base. The primary stems are usually much branched, weakly ascending to nearly decumbent, forming matted clumps. The stems are pale purple, glabrate below, glandular-puberulent, and somewhat viscid in the inflorescence. The leaves are simple and opposite, with narrowly lanceolate to narrowly elliptic blades that are falcate, measuring 3–8.8 cm long and 0.4–2.4 cm wide. The leaf apex is attenuated and somewhat recurved, and the bases are often connated around the stem. The leaf surfaces are glandular-puberulent or glabrate, especially toward the base, with translucent, straight, and erect hairs measuring 0.05–0.15 mm long. The blades are thin and membranous, with weakly revolute margins. The leaves have three principal veins, with the midvein being excentric. The petioles are 0–0.3 (up to 0.6) cm long, and stipules are absent. The flowers are arranged in a terminal inflorescence with 18–149 flowers, measuring 5–22 cm long. The inflorescence is open, moderately to densely glandular-puberulent, with hairs measuring 0.15–0.25 mm long. The bracts are green, narrowly linear-elliptic to subulate, falcate, and often somewhat twisted, with those on the central axis measuring 2–31 mm long and those on the branches and flowers measuring 1–12 mm long. The pedicels are filiform, 7–16 mm long, and inconspicuously flattened. The flowers are bisexual (perfect). The sepals are 3.3–4.5 mm long, lanceolate, green to purple, opaque, strongly reflexed, and convex in the proximal quarter, producing a small transverse bulge. The distal part is concave, sometimes shallowly navicular at the apex, oriented at a 30° angle to the pedicel, moderately to densely glandular-puberulent, with hairs measuring 0.05–0.15 mm long. The margins are conspicuously scarious and ciliate, with an attenuate to subulate apex. The corolla (petals) is absent. There are 10 stamens with dimorphic filaments, the antisepalous whorl measuring 4.5–5.8 mm long and the alternate whorl measuring 4–5 mm long. The anthers are 0.85–1 mm long and yellow. The ovary is superior and 1-celled, with free-central ovule placentation and 3(–4) styles. The fruit is a capsule, approximately 2.5–3 mm long and narrowly ovoid. The seeds are relatively few, measuring 0.6–0.8 mm long, suborbicular, compressed, with a transversely rugose surface. The perisperm is starchy and hard, with true endosperm absent. It is found scattered and sometimes locally common in diverse mesic forests between 360-870 meters.