A green to yellow orchid with very dense appearing calli. The flowers are 4-5cm in length. This orchid is found in sandy limestone country between Lancelin and Geraldton, usually in association with Illyarrie trees, (Eucalyptus erythrocorys). The common name 'Arrowsmith' comes from a locality within the rather narrow distribution of the orchid.
Caladenia x coactescens - Northern Sandplain Spider Orchid
This orchid is a hybrid between the Arrowsmith Spider Orchid and one of the White Spider Orchids (usually the Daddy-long-legs Spider Orchid, Caladenia longicauda subsp. longicauda. It is identified by having predominantly white petals and sepals (from the white spider parent) with fairly dense calli (from the Arrowsmith Spider parent).