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Species Information
Summary: Exidia glandulosa produces blackish gelatinous fruitbodies, forming fused masses of blister-like to cushion-like to brain-like components, with a smooth or warted surface (use a hand lens). Exidia nigricans (With.) P. Roberts, Mycotaxon 109: 220 (2009) has been regarded as a synonym but there is some molecular evidence that it is distinct. E. nigricans is said to produce button-shaped fruitbodies about 2cm across in clusters that quickly coalesce to form, irregular masses 10cm or more across, whereas E. glandulosa produces discrete, top-shaped fruitbodies that rarely if ever coalesce (wikipedia article on E. nigricans accessed April 16, 2016).
Klett(2) separates Exidia glandulosa forma populi Neuhoff as Exidia populi nom. prov. and assigns collections to it from WA, ID, AK, CT, and MN and to Exidia glandulosa from BC, ON, PQ, AZ, CA, IA, LA, MA, MI, MS, NH, NY, SC, and Russia, (Klett). The distribution of Exidia glandulosa includes BC, WA, OR, ID, MB, NB, NF, NS, ON, PE, PQ, YT, AK, AZ, CA, CO, FL, GA, LA, MD, MN, MI, MS, NC, NH, NY, OH, and WI, (Ginns), North America, Europe, and Asia, (Breitenbach), Mexico and Brazil, (Lowy), and the Soviet Union throughout (Raitviir).
Fruiting body: 1-2cm wide, but often fusing with others to form rows or masses up to 50cm across, "beginning as a pallid or translucent blister but soon becoming cushion-shaped to irregularly lobed; reddish-black to olive-black soon becoming jet-black (or black from the beginning)"; upper surface "smooth to minutely roughened or warty"; consistency flabby and gelatinous; stem absent, (Arora), 10-30cm expanses 0.5-1.5cm thick, upper spore-bearing surface cerebriform (brain-like) with undulating folds, margin sharply bounded and not attached to substrate, flesh gelatinous and soft, when dried forms a thin (0.1cm) black shiny membrane on substrate; fruiting body black to brown-black; upper surface punctate with glandular warts, elsewhere smooth and when fresh shiny but otherwise dull and often white-pruinose, (Breitenbach), attaining 20cm or more in the longest dimension, at first colorless, "pustulate, immediately spreading and anastomosing and becoming broadly effused, thick-tuberculate or erumpent and blackish-brown", drying black, spore-bearing surface sparsely or sometimes rather thickly dotted with wart-like papillae, (Martin), no odor or flavor (Lincoff(1)), spore deposit white (Buczacki)
Microscopic: spores 12-14 x 4.5-5 microns, cylindric, +/- allantoid [curved sausage-shaped], smooth, inamyloid, colorless, sometimes with droplets; hypobasidia 16-18 x 8-9 microns, oval, pyriform [pear-shaped], longitudinally septate, with 4 epibasidia; hyphae 1-1.5 microns wide, septa with clamp connections, gelatinized, (Breitenbach), spores 10-16 x 4-5 microns, allantoid, colorless, white in mass; probasidia 10-16 x 7-13 microns, ovate or elliptic, colorless or brownish, becoming cruciate-septate, (Martin), spores 10-16 x 3-5 microns, sausage-shaped, smooth; spore deposit whitish (Arora)
Habitat / Range
"scattered to densely gregarious or in fused rows and masses on rotting hardwood logs and branches", (Arora), on dead hardwood, on the cut surfaces of stumps, as well as on branches on the ground, more rarely on wounded parts of living trees, (Breitenbach), on hardwood, rarely conifer wood: bark, dead branches of live trees, fallen branches, limbs, slash, associated with a white rot, (Ginns), dead hardwood of all sorts, particularly hickory and oak, reported rarely on coniferous wood, (Martin), April to May and November to January (Lincoff(2)), all year (Buczacki)
Similar Species
Exidia nigricans is almost indistinguishable based on macro and micro morphology, "but according to a recent study is widespread in North America and is often misidentified as E. glandulosa", (Siegel(2) with Latin name italicized). E. nigricans may be the correct name for what is commonly called E. glandulosa but will coalesce into one big mass (unlike E. glandulosa), (D. Miller, pers. comm.). |Exidia recisa has a small stem and becomes yellowish brown, (Lincoff). E. recisa has lighter colors (yellowish brown to dark brown as opposed to brownish black to grayish yellowish brown), is more erect, has a very short stem-like base, and lacks the warty surface (McKnight). |Exidia glandulosa forma populi differs primarily in macroscopic characters: it has the inferior surface appressed but free (as opposed to almost entirely adherent to the substrate), and grayish to grayish granulose, and this form lacks surface papillae (it is smooth to finely asperulate and if occasional wart-like structures are found, they are composed of crystals, covered or not by the dikaryophyses), (Klett who uses the provisional combination Exidia populi). |See also SIMILAR section of Bulgaria inquinans and Exidia zelleri.
