Psidium oligospermum is either a small tree or shrub that ranges up to in height and up to in diameter, with smooth, pinkish-grey
bark. It has wide-spreading branches with dotted grey
branchlets with reddish to white or yellowish "
trichomes" or hairs. The branchlets tend to become more smooth at the edges and the bark more stringy, and the
terminal branchlets and
leaves are sometimes covered with a
scurfy reddish bloom. Its leaves are
opposite and
elliptic to
ovate, with the tips of the leaves being
acute to
acuminate. The base of the leaf is narrowly
cuneate and is
decurrent on the stalk of the leaf. The entire leaf is
glabrous and is generally darker on the upper face and paler on the other side. The leaves are generally long and wide, and the
petioles, or leaf stalks, are generally long. The
buds of
Psidium oligospermum are pear-shaped or "
pyriform" and connected to the base of the branchlet, extending about out. The bud is glabrous except for a minute hole at the
apex with a few trichomes protruding outward.
Flowers are white, occur on branches of recent growth, and are relatively small, being in diameter. Its
berries are spherical in shape and are glabrous except for ripples created from
glands in the berries. The berries are yellow when mature and turn black or a reddish-brown when dried. They are in diameter and the "
pericarp", or wall of the berry is about thick. The
seeds are angular, dark, and long, and each
locule contains several. ==Habitat and ecology==