Cladonia sipmanii

{{Short description|Species of lichen}}

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Cladonia sipmanii is a species of fruticose lichen in the family Cladoniaceae. Found in Guyana, it was formally described as a new species in 2000 by Finnish lichenologist Teuvo Ahti. The type specimen was collected by the author from Demerara-Mahaica region; it also occurs in the Guayana Region of Venezuela. It grows in sandy soil and on sandstone; typical habitat includes coastal savannahs. Thamnolic acid, barbatic acid, and 4-O-demethylbarbatic acid are lichen products that have been isolated from this species.