Key to Fungi Bearing Spines or Tooth-like Projections

Note: Irpex lacteus and Spongipellis pachyodon in the key below are actually poroid fungi. Their pores quickly
break down (i.e. portions of the walls between adjacent tubes disappear) to form tooth-like projections. Check near
the margins of Irpex lacteus for evidence of its poroid nature. Certain other poroid fungi (Poroid Key Group A)
also develop a tooth-like fertile surface.

1. Caps present, either 1) individually sessile or stalked, or 2) consisting of the reflexed portions of an
    effused-reflexed growth habit

    2. Fruit body distinctly gelatinous, occurring as stalkless caps 2-8 cm wide or with lateral stalks; upper
        surface of cap whitish to grayish to brownish; underside covered with short, toothlike,
        whitish-translucent spines ...........................................................................Pseudohydnum gelatinosum

    2. Fruit body not with above combination of traits

        3. Fruit body effused-reflexed

            4. Teeth 0.5 to 12 mm long; teeth flattened near margin, cylindrical near center ......Irpiciporus pachyodon

            4. Teeth 1 to 5 mm long                 

                5. Caps ochre with whitish margins; fertile surface tan or ochre, whitish toward margin, bearing spines
                    1-1.5 mm long and often forked ..............................................................Steccherinum ochraceum

                5. Caps white; fertile surface white, bearing white to yellowish flattened teeth 0.5-5 mm long which form
                    from tubes................................................................................................................Irpex lacteus

        3. Fruit body of sessile or stalked caps, not effused-reflexed

            6. Fruit body consisting of tall (15-30 cm high) clusters of large (10-15 cm wide), stalkless, overlapping
                yellowish-white caps with toothed or spiny undersurfaces; spines 0.5-2 cm long; fungus occurs on the
                trunks of living broad-leaved trees...............................................................Climacodon septentrionalis

            6. Fruit body consisting of thin, tough, kidney to fan-shaped to circular caps 2.5-7.5 cm wide with or without
                a short lateral stalk; caps bear brownish spines 1-3 mm long on undersurface; spines appear fused
                and forked at their tips; fungus occurs on logs and fallen branches................... Mycorrhaphium adustum

1. Caps absent, fruit body either 1) entirely resupinate or 2) occuring as a mass of pendulous spines

    7. Fruit body resupinate, appearing crustlike

        8. Spines up to 12-14 mm long ........................................................................................Radulomyces copelandii

        8. Spines shorter than 12-14 mm

            9. Fruit body whitish or distinctly bright yellow or yellow-orange

                10. Fertile surface white, bearing white to yellowish flattened teeth 0.5-5 mm long which form
                      from tubes (see note above) ...................................................................................Irpex lacteus

                10. Fertile surface distinctly bright yellow or yellow-orange

                      11. Fruit body forming spreading patches with downward pointed teeth (5-10 mm long); occurring
                            on fruit trees, particularly apples; odor strong, sweet- fruity or unpleasant ..........Sarcodontia setosa

                      11. Fruit body sheetlike with bright orange-yellow, toothed fertile surface and with bright orange
                            rhizomorphs (10-20 cm long) present; teeth 1-4 mm long ......................Hydnophlebia chrysorhiza

            9. Mushroom tan, ochre or brownish

                12. Fertile surface olive-brown to cinnamon brown; covered with uneven, flattened teeth 3-6 mm
                      long, teeth covered by dark setae (use hand lens) .........................................Hydnoporia olivacea

                12. Fertile surface tan or ochre, whitish toward the margin; covered with spines 1-1.5 mm
                      long and often forked...............................................................................Steccherinum ochraceum

   7. Fruitbody occurring as a mass of pendulous spines; usually whitsh but older specimens may be yellowish

       13. Fruitbody appearing unbranched, occurring as a globose, beardlike mass 10-25 cm
             wide and high with 2-5 cm long spines (teeth) formed in lines and covering the sides......Hericium erinaceus

       13. Fruitbody branched with spines on the branches

             14. Spines 2-4 cm long, tending to be in tufts at ends of branches but also
                   along the branches as well .................................................................................Hericium americanum

             14. Spines 0.3-1 cm long, hanging more or less evenly in rows along the branches....... Hericium coralloides