Butyriboletus floridanus

Butyriboletus floridanus is a species of bolete mushroom in the family Boletaceae. In 1945, American mycologist Rolf Singer described a species he found in Florida during his 1942–3 tenure of a Guggenheim Memorial Fellowship. He originally described it as a subspecies of the eastern North American species "Boletus frostii", but later considered it worthy of distinct species status in a 1947 publication. Although known as a species of "Boletus" for over 50 years, the current interpretation, based on molecular phylogenetic analysis, is that the taxon belongs in the genus "Butyriboletus".
"Butyriboletus floridanus" differs from "Butyriboletus frostii" in having a lighter cap color and in the texture of the cap surface: the subspecies is tomentose (covered with dense, short, soft, matted hairs) or velutinous (like velvet), compared to the relatively smooth surface of "B. frostii". Singer notes that although the physical characteristics between the two taxa may be blurred and are hard to define, the area of origin is a reliable indicator of subspecies status. "B. floridanus" is found on shaded lawns and scrubland in open oak stands in non-tropical regions of Florida, typically on grassy or sandy soil. It grows under or near several oak species, including Chapman oak ("Quercus chapmanii"), swamp laurel oak ("Q. laurifolia"), and southern live oak ("Q. virginiana"), and it fruits between May and October.