Annual grass-like forb, prostrate or 2-8cm tall. Leaves alternating along the stems, appearing basal, more or less sheathing at the base, 2-7cm long, about 1mm wide, linear, hairless. Flowers greenish white with a yellow centre and 0 petals. Flower heads compound, broadly hemispherical, borne singly at the ends of the stems.
Superficially resembles Isoetopsis graminifolia . The flower heads of Myriocephalus rhizocephalus are compound, composed of partial flower heads, while the flower heads of Isoetopsis graminifolia are simple, not composed of partial flower heads.
Description and photo (as Myriocephalus rhizocephalus var. rhizocephalus) in G.M. Cunningham, WE Mulham, PL Milthorpe and J H Leigh (1981 and later printings) Plants of Western New South Wales page 673