Caladenia septuosa is a terrestrial, perennial, deciduous, herb with an underground tuber and a single erect, sparsely hairy leaf. The leaf is long, wide and dull green. Usually only a single greenish-cream flower across is borne on a spike tall. The sepals, but not the petals, have brown, club-like glandular tips long. The dorsal sepal is long, wide and curves forward. The lateral sepals are long and wide, spread apart and curve downwards. The petals are long, about wide and arranged like the lateral sepals. The labellum is long and wide, green and white with a dark red tip. The sides of the labellum turn upwards and have three or four pairs of thin green teeth up to long, and the tip curves downwards. There are four or six rows of dark red calli up to long, along the labellum mid-line. Flowering occurs from September to October.
