Caladenia petrensis A.P.Br. & G.Brockman

Plants solitary or in small crowded tufts. Leaf linear, 30–90 × 6–8 mm. Flower stem 170–370 mm tall, 1-or 2-flowered. Flowers 50–60 mm across, dull creamy yellow with maroon stripes, spots and blotches; sepals and petals with long, glandular, brownish black, filamentous tips. Dorsal sepal erect, 40–70 × 2–3 mm. Lateral sepals spreading near base then pendulous, 50–70 × 3–4 mm. Petals similarly arranged, 50–60 × 2–4 mm. Labellum stiffly hinged, 12–15 × 8–10 mm, cream with prominent deep red stripes and blotches; margins with numerous short, blunt teeth; tip recurved. Calli to 1.5 mm long, anvil-shaped, creamy yellow to creamy white, 10–16 pairs in 2 rows. Column 11–14 × 3–5 mm, cream with red markings.

Localised; growing under wattles and with dense forbs in seasonally moist soils on ironstone hills, or around the base of hills and along rocky streams and gullies.