The sessile flowers of Glumicalyx flanaganii grow in many-flowered head-like spikes that nod. The yellow-green, hairy bracts with pointed tips that sheathe the flowers are the glume-like calyces giving the genus its name. A glume is the bract or leaf-like structure below a spikelet in the inflorescence of grasses or the flowers of sedges.

The five oblong to rounded petal lobes of each flower are brownish orange on the inside, creamy white on the outside, as on the thin, cylindrical corolla tube. The four stamens with pale anthers protrude from the flower mouth, as does the style that is even longer (Manning, 2009).