Key to Crust and Parchment Fungi (no pores, teeth, or gills)

1. Fruit body occurring as 1) projecting shelf-like or petal-like caps (parchment-like in texture) with or without
    resupinate (crust-like) portions or 2) flattened cup-like or disc-shaped structures, circular to irregular in outline
    with margins free and elevated from the substrate

    2. Fruit body a flattened cup-like or disc-shaped structure, circular to irregular in outline with margins free and
        elevated from the substrate; fruit bodies may be confluent ....................Aleurodiscus wakefieldiae

    2. Fruit body occurring as projecting shelf-like or petal-like caps (parchment-like in texture) with or without
        resupinate (crust-like) portions

        3. Fertile resupinate surface brown with conical setae (use hand lens), surface smooth or cracked; caps
            brownish and concentrically zoned; flesh turns blackish with KOH; fruit bodies often fuse laterally to form
            larger colonies............................................................................................Hydnoporia tabacina

        3. Fertile surface without conical setae; flesh not blackish with KOH

            4. Cap pale gray/silvery and covered with tiny radiating silky fibers; caps 0.5-1 cm wide but often laterally
                fused; fertile surface whitish, growing dead twigs and branches of hornbeam
                (Carpinus caroliniana) ....................................................................................... Stereum striatum

            4. Cap typically hairy but color, size, and substrate not as above

                5. Caps projecting up to 7 cm from substrate; distinctly zoned with shades of dark
                    brown, rust, and gray; fertile surface buff to cinnamon-buff; typically forming
                    individual brackets rather than fusing ...................................................................Stereum ostrea

                5. Caps projecting 0.3-3 cm from substrate, zonate, often fused laterally

                    6. Flesh turns dark red or oozes reddish fluid where scratched or bruised ........Stereum gausapatum

                    6. Not as above

                        7. Cap covered with coarse, stiff hairs; fertile surface buff to gray......................Stereum hirsutum

                        7. Cap silky hairy, smooth and shiny near margin, radially furrowed; fertile surface orange but fading
                            to cinnamon-buff, slightly ridged where caps join .......................................Stereum complicatum

1. Fruit body appearing as 1) a pretzel-like network of interwoven strands or 2) a sheetlike or crustlike spreading
    form or 3) a swollen, blackish spindle-like growth on cherry (Prunus) twigs or 4) a large, cracked, blackish,
    knob-like or canker-like growth on birch (Betula) trunks or 5) closely arranged, broken pieces of whitish to
    grayish to tanish ceramic tile

    8. Fruit body appearing as an interwoven network of yellow to tawny strands ...................Hemitrichia serpula

    8. Fruit body not as above

        9. Fruit body sheetlike, crustlike, spreading in appearance

            10. Fruit body soft, fluffy, slimy, yellowish, spreading mass at first; maturing into dry, ochre to red-brown
                 mass up to 20 cm long, 1-3 cm thick; with a brittle crust and blackish, powdery, dry
                 spore mass underneath .................................................................................................Fuligo septica

            10. Fruit body not as above

                  11. Fruit body hard, blackish, carbon-like

                        12. On stumps and roots of decaying hardwoods; surface irregular with bump-like pores giving finely
                              roughened appearance; flesh 3-6 mm thick; often brittle and easily detached........Kretzschmaria deusta

                        12. On decaying hardwood branches, often encircling them; surface finely roughened to nearly
                              smooth and shiny, sometimes cracked; flesh 0.2-1.5 mm thick..................................Diatrype stigma

                  11. Fruit body brown to reddish-brown surrounded by whitish margin..........................Peniophora albobadia

   9. Fruit body as swollen, blackish spindle-like growths on cherry twigs, canker-like growths on birch trunks, or
            as closely arranged, broken pieces of whitish to grayish to tanish ceramic tiles

            13. Fruit body as blackish, spindle-shaped swellings on cherry twigs or canker-like growths on birch trunks

                  14. Fruit body as spindle-like growths or knot-like swellings on cherry (Prunus) twigs and
                        branches.....................................................................................................Apiosporina morbosa

                  14. Fruit body as knob-like or canker-like growths on birch (Betula) trunks ...........Inonotus obliquus

            13. Fruit body hard and woody; appearing as closely arranged, small, broken pieces of whitish
                  to pinkish-buff tiles typically on debarked oak logs and stumps ..........................Xylobolus frustulatus