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

Summary:
Hydnum repandum itself has not been found in North America. The term Hydnum repandum group is an artificial group to describe what we have been calling Hydnum repandum in North America (excluding Hydnum umbilicatum). |Features of the Hydnum repandum group include a convex to depressed cap up to 17cm across or larger that is tan to pale orange or even reddish-tawny; white flesh; whitish to pale orange teeth; a relatively short stem that is cap-colored or paler; a bruising reaction to orange on cap, in cap flesh, and on the teeth and stem; white spore deposit; and microscopic characters. |Following the molecular work of Niskanen(10), Hydnum repandum is well documented only from Europe. According to Niskanen(10), the most closely related species in North America is Hydnum neorepandum [here considered a synonym of Hydnum washingtonianum following Swenie(1)] - Niskanen(10) documented that species from NL and from an ectomycorrhizal root tip in CA, but they also described several other new Hydnum species using Pacific Northwest collections. |Hydnum olympicum will also belong to this group until it is clear how to tell it apart from Hydnum washingtonianum without measuring spores. Hydnum melleopallidum can be similar and spores are similar, but the fruitbodies are smaller than those of Hydnum washingtonianum. |Hall found what he called the type variety (described below) in WA as well as two other varieties (the first only tentative because it is basically an intermediate between H. repandum and H. umbilicatum): 1) Dentinum repandum var. macrosporum Hall & Stuntz nom. prov. (spores 9.0-9.8 x 7.6 microns) and cap "pinkish-buff" to "cinnamon-buff" (like var. repandum and unlike Hydnum umbilicatum, var. macrosporum has a large convex or slightly depressed cap), and 2) Dentinum repandum var. album (Quel.) K.A. Harrison = Hydnum repandum var. album (Quel.) Rea, with white cap and smaller spores 6.7-7.3 x 4.7-6.7 microns, (Hall).

H. repandum group is widely distributed in United States and Canada, including FL, NC, NY, PA, and TN, and is common in Europe, (Coker). There are collections from WA, OR, and CA at Oregon State University, and collections from BC at Pacific Forestry Centre and University of British Columbia. The University of Washington also has collections from AK. It has been reported from ID by Andrew Parker, pers. comm.

Cap:
2-17(25)cm, broadly convex to flat or depressed, "margin often wavy or deeply indented and at first inrolled"; "pale flesh-color to pale or dull orange, orange-tan, salmon, tan, or pale cinnamon to reddish-tawny (but white to creamy in var. album)", bruised areas often darker orange; dry, more or less smooth, but sometimes cracking into scales when old, (Arora), 2-6.5cm across, (fruitbody up to 7cm tall), convex to slightly depressed, margin inrolled when young, becoming irregular and wavy when old, ''yellowish white'' to ''pale orange'' or ''light orange'', becoming ''dark orange'' when bruised; smooth to slightly furfuraceous, (Hall), pale tan to rusty cinnamon or pale orange, (Phillips), pale orange-yellow to pale reddish brown, (McKnight), buff to buffy orange, never white (except in var. album), with the appearance and feel of leather, (Coker)

Flesh:
thick, firm, brittle, occasionally zoned concentrically; white, usually turning yellow to yellow-ocher or orange-brown when bruised, (Arora), up to 2cm thick, "homogeneous, pulpy or fleshy-fibrous"; ''white'' when fresh, becoming "ochraceous-orange" when cut, in stem fleshy-fibrous, pallid, (Hall), white, at times changing to dull yellow or orange when bruised, (Coker), cream staining orange, (Phillips)

Teeth:
0.2-0.7cm long, "slender, brittle but soft, usually decurrent"; "whitish to yellowish, salmon-buff, or pale orange, bruising dark orange to ochraceous", (Arora), up to 0.7cm long, 2-4 per square mm, irregularly decurrent to nondecurrent, fleshy, round in cross-section, subulate [awl-shaped], extending all the way to margin; ''yellowish white'' to ''pale yellow'', becoming "ochraceous-orange" when bruised, (Hall), long and short teeth intermingled, some flattened or fused, (Coker)

Stem:
3-10cm x (0.5)1-3(5)cm, central or off-center, equal or widening in lower part or occasionally narrowing downward, firm; "white or colored like cap but usually paler", bruising ocher to dark orange-brown; "smooth or downy at base", (Arora), 4.5-9cm x 0.6-1.5cm, central to slightly off-center, ''yellowish-white'' to ''pale yellow'', becoming "ochraceous-orange" to "zinc orange" when bruised, (Hall)

Odor:
mild (Arora), none or slightly fungoid (Hall)

Taste:
mild to somewhat bitter or peppery, (Arora), none (Hall), mild to rather sharpish (Breitenbach), older specimens may taste bitter (Sept(1))

Microscopic:
spores 6.5-9 x 5.5-8 microns, broadly elliptic to nearly round, smooth, (Arora), spores 8.0-8.7 x 6.2-7.0 microns, round to subelliptic, smooth, inamyloid; basidia 3-4-spored, 45-50 x 4.7-6.7 microns, clavate; cystidia absent; hyphae 2.7-4 microns wide, thin-walled, with abundant clamp connections, (Hall), spores 7-8.5 x 6-7 microns, (Bessette), spores 6.5-8.5 in diameter, round, (Phillips), spores 6-7 x 5-6 microns (Lincoff(1)), spores 7-8 x 6.3-7.4 microns, var. albidum 7-8.5 x 5.5-7 microns, (Coker)

Spore Deposit:
white (Arora)