Lyperanthus serratus, commonly called rattle beaks, is a species of orchid that is endemic to the south-west of Western Australia. It derives its common name from the fact that the flowers rattle if gently shaken.
Lyperanthus serratus is a tuberous, perennial herb, NaNsigfig=1NaNsigfig=1 high with 3 to 10 green, yellow and brown flowers, NaNsigfig=1NaNsigfig=1 wide, from September to October.[1] The flowers have white (non-secreting) glandular hairs on the labellum. There is a single leaf which is arched, ribbed, leathery and linear, about 35sigfig=1NaNsigfig=1 long and 1.5sigfig=1NaNsigfig=1 wide.[2] [3] A powdery bloom covers the entire plant, except for the innermost parts of the flower. The single leaf is lance-shaped, NaNsigfig=1NaNsigfig=1 long and NaNsigfig=1NaNsigfig=1 wide, dark green with a paler lower surface.[4]
The species was first described by John Lindley in 1840 in his The Genera and Species of Orchidaceous Plants.[5] The type specimen was collected by Drummond near the Swan River. Lindley noted "This has, when dried, so much the appearance of L. suaveolens, that I mistook it for that species. It is however a much stouter plant; and, as will be seen by the above character, the labellum is altogether different."The specific epithet (serratus) refers to the white calli found on the labellum, appearing like serrations on its edge.[6] [7]
The species occurs in the Avon Wheatbelt, Esperance Plains, Jarrah Forest, Swan Coastal Plain and Warren biogeographical regions of Western Australia on sand, loam or sandy clay. It grows in a variety of habitats including forest, woodland and heath and often grows through reasonably low, dense vegetation.[8]
As with other Australian terrestrial orchids, Lyperanthus serratus is not well known in cultivation but success has been achieved with the closely related Lyperanthus suaveolens.[9]