Description: This blue-white to grey powdery lichen favours acid-barked trees such as birch and alder, but especially conifers and conifer plantations. Spot tests K+ yellowish, all else negative. It has fine powdery granules. White hyphae are rather clingy so are abundant in the crevices in the substratum. However, they do not form a hypothallus. In Ireland, it occurs mainly in the north and west.

Key Identification Features:

• Thallus blue-white to grey; all reactions negative except K+ yellowish
• Granules fine, powdery; hyphae cling to crevices; very acid-barked trees.

Original text submitted by Vince J. Giavarini

Distribution Map from NBN: Lepraria jackii at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Lepraria jackii at iNaturalist World Species Observations database.