Carmichaelia williamsii (common name William's broom or giant-flowered broom)[1] is a species of plant in the family Fabaceae. It is found only in the North Island of New Zealand.[1] Its conservation status (2018) is "At Risk (relict)" under the New Zealand Threat Classification System.
Carmichaelia williamsii is the only yellow-flowered native broom, and it is distinguished from the introduced broom (Cytisus scoparius (L.) Link) by its light green, much wider, and more flattened branches, together with its larger, pale-yellow flowers which have purple or red veins, and its late-winter flowering (July to October, though flowering can occur throughout the year).[1]
The species was first described by Thomas Kirk in 1880. The earliest record in AVH, SP026354 was collected by Bishop William Williams in 1879 somewhere in the North Island,[2] and for whom Kirk named it.
It is a coastal species found in open forest, scrub, cliff faces and on scree.[1]