E-Flora BC: Electronic Atlas of the Flora of British Columbia

Summary:
Features include 1) a top-shaped to funnel-shaped, reddish brown to yellowish brown or wine-brown cap with a white growing margin, 2) tough flesh zoned reddish brown and darker in stem, 3) teeth that are pinkish brown or reddish brown or purplish brown, 4) variably shaped stem colored similarly to cap and blackening when bruised, 5) weak farinaceous odor and somewhat bitter taste, and 6) growth in forests with caps often joined together. Hydnellum scrobiculatum var. zonatum, also known as Hydnellum zonatum, is considered a synonym. Hydnellum concrescens is a member of the Hydnellum scrobiculatum group, in which we currently include Hydnellum concrescens, Hydnellum scrobiculatum, and Hydnellum subsuccosum. These three, along with 2 unnamed species are included in the Hydnellum concrescens complex of Baird(3) that reflects a clade in their DNA research in southeastern North America. The Baird(3) molecular study showed 5 branches, one considered to be H. concrescens and another Hydnellum subsuccosum. See the NOTES under Hydnellum scrobiculatum group for a discussion of whether one of those branches is H. scrobiculatum.

There are collections at the University of British Columbia for BC and WA, collections at Pacific Forestry Center from BC (determined by K. Harrison as H. scrobiculatum var. zonatum), a collection from OR (as Hydnellum parvum) at Oregon State University, collections from WA and OR at University of Washington (some as H. zonatum). (Some of these collections in various herbaria might fall under Hydnellum subsuccosum described in 1964.) Hydnellum concrescens is quite common under hardwoods in eastern North America but also occurs on the west coast both in its normal form and a diminutive one whose cap is 4cm broad or less, (Arora). Hydnellum concrescens is widespread in the northern hemisphere, and found throughout Europe (including the United Kingdom and Switzerland), commonly in some areas, and is also present in North America and much of Asia, (Pegler(3)).

Cap:
2-8cm across, "soon depressed, irregularly lobed"; reddish brown to yellow-brown, "sometimes with blackish patches, and with margin whitish at least when young"; "tomentose becoming smooth, with distinct radial grooves and ridges and with concentric zonation", (Pegler), 2-5(7)cm across, irregularly rounded, somewhat turbinate [top-shaped] to infundibuliform [funnel-shaped] with a wavy margin; whitish when young then red-brown to wine-brown, with white growing marginal zone; depressed center with small erect scales, the rest of the upper surface "radially ribbed and concentrically zoned", (Breitenbach), 2-7cm across, centrally depressed; "white to creamy-pink and velvety at first becoming fibrous-scaly and tan to dark brown in concentric zones, often with blackish blotches"; radially ridged, covered in coarse knobs or secondary caps, (Phillips(2))

Flesh:
thin; reddish brown, zoned, often darker in the stem, (Pegler), corky, tough; "zoned, dark wine-red, turning almost black in the stipe", (Breitenbach)

Teeth:
(0.1)0.2-0.3(0.4)cm long, slender, decurrent; rusty brown becoming pale buff, (Pegler), up to 0.3cm long, pink-brown to red-brown, (Breitenbach), 0.1-0.3cm long, whitish then pinkish brown, finally dark purplish brown, (Phillips(2))

Stem:
up to about 5cm long, 0.2-1cm wide, usually central, variable in form, cylindric or narrowing downward, often with bulbous base; colored as cap, blackening where bruised; surface velvety, (Pegler), 1-3cm x 0.3-0.8(1)cm, solid, cylindric and gradually merging with cap, base sometimes rather enlarged; light brown, blackening when bruised; dull, finely tomentose, (Breitenbach), 0.2-1cm wide, colored as cap; velvety to matted, (Phillips(2))

Chemical Reactions:
flesh in alkali solution "rapidly dark green, and exuding a green or blue-green stain"

Odor:
weak, of meal [farinaceous] (Pegler), weakly farinaceous, (Breitenbach), mealy (Phillips(2))

Taste:
slightly bitter (Pegler), somewhat bitter, (Breitenbach)

Microscopic:
spores 4.5-5.5 x 3-3.5 microns, yellow-brown, tuberculate; basidia 4-spored, 29-37 x 5-6.5 microns, narrowly clavate; hyphae in spines (2)3-3.5(4) microns wide, "often branched, flexuous, yellow-brown, remotely septate", clamp connections absent; context hyphae 4-6 microns wide, pale yellow-brown to colorless, or with pale yellowish pigment, often branched, septate, clamp connections absent, (Pegler), spores 4.5-6 x 3.5-4.5 microns, nearly round, "coarse-tuberculate, light brown, some tubercles developed into double tubercles", iodine negative; basidia 4-spored, 28-35 x 5.5-7 microns, narrowly clavate, without clamp connection; cystidia not seen; hyphal system monomitic, subhymenial hyphae 2-4 microns wide, +/- thick-walled, branched, septa without clamp connections but often with visible dolipore; hyphae in cap 1.5-4 microns wide, sinuous, brownish, septa without clamp connections, (Breitenbach), spores 5.5-6 x 4-4.5 microns, irregular in outline, (Phillips(2))

Spore Deposit:
dull brown (Phillips(1))