Myristica insipida is a small, single-stemmed tree usually growing up to in height but it may reach in certain conditions. The trunk is cylindrical and straight, in mature trees it may exceed
DBH. The bark is dark brown with numerous fine vertical fissures. As with other members of the family, this species displays the distinctive habit known as "myristicaceous branching", in which up to five primary branches are produced in a whorl from the trunk at regular intervals (see
Gallery). The branches extend horizontally from the trunk and the
twigs carrying the leaves are also held in a horizontal plane, creating a layered appearance. The
exstipulate leaves are
simple and
alternate, dark green and
glabrous (hairless) on the upper surface, much paler and glabrescent (almost glabrous) underneath, with 6 to 14 pairs of lateral or secondary veins. They are
elliptic to
ovate in shape, often with an
acuminate tip (commonly called a "drip tip"). They are variable in size, from wide by long. The
petiole, or leaf-stalk, measures between long and is channelled on the upper side. The lateral veins are evident on both sides of the leaf, while the reticulate (net-like) tertiary venation is only visible on the lower surface. The buds and new shoots are typically covered in very fine, dense brown hairs. This species is
dioecious, meaning that
staminate (functionally male) flowers and
pistillate (functionally female) flowers are produced on separate plants. The
inflorescences are
axillary fascicles (clusters), emanating from a small,
persistent, woody
tubercle in the leaf axil (see
Gallery). The male flowers measure up to long by wide on a
pedicel measuring up to long. Female flowers are up to long by wide on a pedicel. The fruits which follow are a
dehiscent capsule measuring between long by wide. They are
ellipsoidal in shape and covered in fine, dense mid-brown hairs. The large single seed is also ellipsoidal, dark brown in colour and surrounded by a bright-red, net-like
aril.
Phenology Flowering appears to occur in response to rain events beginning in the late spring, with those at higher elevations flowering later than those at low elevations, and there may be a second flowering in a reduced number of individuals in the late summer. Male plants have been found to flower around 10–17 days earlier, and significantly longer, than female plants. Fruits reach maturity around September, when they dehisce and reveal the seed inside. Between that time and the beginning of flowering (around 4–6 weeks) the trees put out a flush of new growth. ==Taxonomy==