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Range of Caladenia flava — Range of *Caladenia flava*.

Cowslip Orchid
Caladenia flava R.Br. 1810

Synonyms

Caladeniastrum flavum (R.Br. 1810) Szlach. 2003

Notes

The Cowslip Orchid is one of the most abundant and most easily recognisable orchids of Western Australia. Cowslip Orchids can be found in almost every area of bushland across south-western WA and thrive in a variety of different habitats. They often form extensive clonal colonies which can sometimes be made up of hundreds of individuals. Cowslip Orchids also have a very extended flowering period lasting from early July near Kalbarri until early December in the far south-west of WA.

The Cowslip Orchid is divided into four subspecies:

Cowslip Orchid (Caladenia flava subsp. flava)
This is the most common and widespread subspecies and can be found south-west of a line from Kalbarri to Israelite Bay. It usually flowers from July until October (depending on location) and is identified by its yellow flowers with a regular pattern of red blotches or lines on the dorsal sepal and petals. The red markings are highly variable and can be missing entirely.
Kalbarri Cowslip Orchid (Caladenia flava subsp. maculata)
This subspecies is found in near-coastal areas around Geraldton and Kalbarri. It flowers from July until early September and is characterised by its irregular pattern of red blotches on the dorsal sepal and petals (hence the name maculata). Again, the red markings vary in size and extent.
Brookton Highway Cowslip Orchid (Caladenia flava subsp. ‘late red’)
This distinctive, yet to be formally named subspecies is found along the Darling Scarp and across the southern Wheatbelt south-east of Perth. It flowers slightly later, from late September until early November, and is characterised by extensive red markings on the dorsal sepal and petals as well as its leaf which is usually much longer than the flower stalk.
Karri Cowslip Orchid (Caladenia flava subsp. sylvestris)
This subspecies is mainly found in higher-rainfall areas in the far south-western corner of Western Australia and flowers much later, typically from October until December. It is mainly found in forests (hence the name sylvestris), in particular Karri forests, and is characterised by its very long flower stalk, long and slender leaf, and yellow and white flowers with red markings on the dorsal sepal and petals.

Cowslip Orchids occasionally form hybrids with other Caladenia species, in particular with the Pink Fairy Orchid (Caladenia flava × Caladenia latifolia) and the Little Pink Fairy Orchid (Caladenia flava × Caladenia reptans). These hybrids are easily recognised by their unique colour which is usually somewhere in between the yellow and pink colours of their parents.

Curiously, there are two unusual colour forms of the Cowslip Orchid which are restricted to a small area of the Darling Scarp and have been described as separate species. The White Primrose Orchid (Caladenia lateritica) has white instead of yellow flowers and looks exactly like the occasionally encountered white colour form of the Cowslip Orchid. The Pink Primrose Orchid (Caladenia rosea) has pink instead of yellow flowers and looks like some of the hybrids between the Cowslip Orchid and the Pink Fairy Orchid (Caladenia latifolia). The taxonomic status of these two colour forms is uncertain.