Mycena bulliformis B.A. Perry & Desjardin, 2016

Perry, Brian A. & Desjardin, Dennis E., 2016, New species of Mycena (Basidiomycota, Agaricales) from California, Phytotaxa 269 (1), pp. 33-40 : 36-39

Mycena bulliformis B.A. Perry & Desjardin , sp. nov. ( Figs. 1b , 3 )

MycoBank No. 563355

Previous references:

Mycena bulliformis B.A. Perry & Desjardin , nom. prov., A Taxonomic Investigation of Mycena in California, M.S. Thesis, San Francisco State University, San Francisco, p. 130 (2002).

Diagnosis:—Pileus violaceous brown to reddish brown or grayish red, often nearly grayish pink in age, lacking yellow coloration. Stipe pink to pinkish gray when young, lacking yellow coloration. Pileipellis and stipe cortical hyphae ornamented with coarse, inflated excrescences. Cheilocystidia subcylindrical to irregular-lageniform or fusoid-ventricose in shape, giving rise apically to one or more, cylindrical to sinuous excrescences.

Holotype:— UNITED STATES. California: Marin Co., Mt. Tamalpais State Park, Benstein Trail , Rock Springs area , cespitose on the bark of living Pseudotsuga menziesii , 22 December 1992, D. E. Desjardin 5614 ( SFSU).

Description:— Pileus ( Fig. 1b ) 10–25 mm diam., obtusely conical to paraboloid, expanding with age; the margin slightly inflexed initially, edges crisped and occasionally eroding or splitting with age, pellucid-striate when moist, striate to sulcate in age; surface dull, dry, covered with a hoary bloom when fresh, glabrescent; the disc violet-brown (10–11F5–7) to deep grayish red or grayish violet (12–13E5–6) initially, becoming more grayish to brownish red/violet with age, the margin paler, grayish red (9C3) to pale reddish brown (9D5–6), becoming grayish pink with moisture loss. Context thin, up to 1 mm thick, white. Lamellae ascending-adnate, with or without a short decurrent tooth, subdistant with 1 or more series of lamellulae (18–20 reaching the stipe), narrow to moderately broad (up to 2.5 mm); white to buff, often with pink tones; edges violet to violet-brown (11–12D6), rarely concolorous with lamellae sides. Stipe 25–72 × 1.5–3 mm, central, terete to somewhat flattened and once-cleft, hollow; surface dull to polished, dry, the apex white-pruinose initially, glabrescent; white with pink tones or pinkish gray (9-11C3) overall when young, in age the apex remaining pinkish gray with the base becoming gray to brownish gray; the base sparsely covered with short, white fibrils. Odor mild or musty. Taste mild to unpleasant.

Basidiospores ( Fig. 3a ) 9.6–12.2(–12.6) × (5.6–)6.2–7.7(–8.1) μm [x m = 11.0 ± 0.9 × 6.8 ± 0.5 μm, Q = 1.4–1.9, Q m = 1.6 ± 0.1, n = 50 spores], ellipsoid to broadly ellipsoid, smooth, thin-walled, amyloid. Basidia ( Fig. 3b ) 27–37 × 7.2–9.6(–11.3) μm, clavate, 4-spored, clamped, sterigmata up to 8.8 μm in length; basidioles clavate. Cheilocystidia ( Fig. 3c ) 24–59 × 7–16 μm, subcylindrical, irregular-lageniform or fusoid-ventricose, apically giving rise to one or several, short to long, cylindrical to sinuous, simple or rarely branched excrescences, 4.0–41.6 × 2.4–4.0 μm; thin-walled, clamped, filled with brownish violet, granular contents when mounted in water or Melzer’s reagent; forming a sterile lamellar edge. Pleurocystidia absent. Pileipellis a cutis ( Fig. 3d ); hyphae 2.4–4.8(–8.1) μm diam., clamped, thin-walled, smooth or covered with coarse, inflated or more rarely cylindrical, often furcate excrescences, 2.0–15.2 (–23) × 1.6–6.4 μm diam.; hyphae filled with copious oily droplets, or with reddish brown, granular contents when mounted in water or Melzer’s reagent. Hypodermium composed of inflated, elongate cells, brownish vinescent in Melzer’s reagent. Pileus and lamellar trama similar to hypodermium. Stipe tissues monomitic, parallel, brownish vinescent in Melzer’s reagent. Stipe cortical hyphae ( Fig. 3e ) 2.0–3.2 μm diam., clamped, thin-walled, covered with scattered to densely spaced, lump-like to strikingly inflated, coarse excrescences, 3.2–22 × 3.2–9.6 μm; terminal cells repent, up to 8.8 μm diam., covered with excrescences similar to those of the cortical hyphae.

Habit, habitat, and known distribution:—Cespitose on bark and wood of standing and dead Pseudotsuga menziesii (Mirbel) Franco , and possibly that of Arctostaphylos glandulosa Eastw. , North and Central Coast Ranges and the Sierra Nevada Foothills, November to January.

Etymology:— bulliformis –in reference to the large, rather coarse, bulliform excrescences of the pileipellis and stipe cortical hyphae

Additional Specimens Examined:— UNITED STATES. California: Marin Co., Mt. Tamalpais State Park, Simmons Summit south, under Arctostaphylos glandulosa , possibly on buried wood, 13 December 1996, J. R. Blair 270 (SFSU). Mendocino Co., Jackson State Demonstration Forest, junction of roads 408 and 409, cespitose on bark of Pseudotsuga menziesii , 23 November 2002, DED 7532 (SFSU); Jackson State Demonstration Forest, Mendocino Woodlands Camp, cespitose on bark of Pseudotsuga menziesii , 11 November 2007, BAP 547 (SFSU).

Comments:— Mycena bulliformis belongs in sect. Rubromarginatae Singer ex. Maas Geest. due to the violaceous lamellar edges, red to violaceous tones on the pileus, and lack of latex. Within North America, M. bulliformis is most likely confused with M. rubromarginata (Fr.: Fr.) P. Kumm. sensu Maas Geesteranus (1986, 1992), and within California, M. purpureofusca (Peck) Sacc. Mycena rubromarginata has been reported from the bark of spruce and fir throughout northern North America and as far south as Oregon in the west and North Carolina in the east ( Smith, 1947). Micromorphologically, M. bulliformis resembles M. rubromarginata in the shape of its cheilocystidia, but differs in the shape and size of both the pileipellis and stipe cortical hyphae excrescences. Mycena rubromarginata is characterized by more or less narrow, cylindrical, and very long pileipellis excrescences (up to 36 μm; Maas Geesteranus 1986, 1992), and short, cylindrical stipe cortical hyphae excrescences, whereas M. bulliformis has pileipellis and stipe cortical hyphae excrescences that are generally shorter and coarser and/or inflated (2.0–15.2 (–23) 1.6–6.4 μm diam.). In addition, M. bulliformis has some pileipellis hyphae that are smooth, a condition not reported in M. rubromarginata . Mycena purpureofusca , in contrast, is typically much more purple to violaceous in pileus, stipe and lamellar edge coloration than is M. bulliformis , often has a raphanoid odor, and can be further distinguished by pileipellis and stipe cortical hyphae that are embedded in gelatinous matter.

Additional species of section Rubromarginatae that superficially resemble M. bulliformis include, M. seynii Quél. , M. seynesiella Malençon , and M. renati Quél. Microscopically , M. bulliformis differs from M. seynii in having slightly shorter spores [10.5–15(–16) × 6–7.5(–8) μm in M. seynii ; Robich 2003], and cheilocystidia that are typically irregular-lageniform in shape or with more than one long, coarse excrescense. The typical cheilocystidia in M. seynii are subcylindrical to clavate or subfusiform, and with or without one or more shorter, coarse excrescences ( Kühner 1938, Maas Geesteranus 1986, 1992, Robich 2003). Macromorphologically, M. bulliformis can be distinguished from M. seynii by the lack of yellow tones that often develop on the pileus of M. seynii , as well the lack of a rooting stipe, and the lack of a dense coating of whitish fibrils or tomentum on the lower portion of the stipe that is common in M. seynii . Maas Geesteranus (1986, 1992) reported the presence of “watery white to dingy whitish” coloration on the lower stipe in M. seynii , a condition that has not been observed in M. bulliformis . Moreover, M. bulliformis is not known to grow on the fallen cones or wood of Pinus spp ., which is reported to be the common habit of M. seynii ( Kühner 1938, Maas Geesteranus 1986, 1992, Robich 2003). Mycena seynesiella can be differentiated from M. bulliformis by the presence of a removable, gelatinous pellicle in the former species, as well as a chlorine-like or nitrous-like odor, and the presence of copper and pale honey tones that develop on the pileus and stipe respectively. Neither M. seynii nor M. seynesiella have been reported from North America. Mycena renati differs from M. bulliformis in forming differently shaped cheilocystidia, has smaller basidiospores (8.8–10.4(–10.8) × 4.8–5.6 μm), and in forming a distinctly yellow stipe ( Maas Geesteranus 1992, Robich 2003). Mycena renati was reported from decayed conifer wood in North America, including California, by Smith (1947, as Mycena rubromarginata var. laracis Smith = Mycena elegantula Peck ). However, Smith’s concept of this taxon has proved to include several distinct species (see Perry & Desjardin 1999), and to our knowledge M. renati has not been documented from California.

Pairwise comparison of ITS sequence data from a single collection of M. bulliformis (KX513844) with sequences of M. rubromarginata from Austria (JF908430), Denmark (KX513845), Norway (JQ358810), and British Columbia (EF530939, KP454009, HM240536, HM240537) indicate 4.6%–5.0% difference between aligned, overlapping regions, while comparison of the sequences of M. rubromarginata indicate a difference of only 0–0.35% for the same marker. Comparison of sequence data for the more conserved nLSU from the same M. bulliformis collection (KX513848) with sequence data of M. rubromarginata from Germany (AY20745) and Denmark (KX513849), indicate a 1.1% difference between aligned, overlapping regions. In contrast, the sequences of M. rubromarginata from Germany and Denmark are 100% identical throughout all overlapping regions. Similar pairwise comparisons of ITS sequence data for M. bulliformis with existing sequences of M. purpureofusca from British Columbia (HQ604763, HQ604764, HQ604765, HQ604766, HQ604767) and Norway (JQ358809), indicate differences of 1.7–1.9% between aligned, overlapping regions. Comparison of the sequence data for these same M. purpureofusca collections indicates pairwise differences of only 0.0–0.17%.

Figures

FIGURE 1. a. Mycena nivicola (MGW s.n., photo by Michael G. Wood). b. Mycena bulliformis (BAP 547, photo by Brian A. Perry) Scale bars = 10 mm.

FIGURE 3. Micromorphological features of Mycena bulliformis (HOLOTYPE–DED 5614). a. Basidiospores. b. Basidia and basidiole. c. Cheilocystidia. d. Pileipellis hyphae. e. Stipitipellis hyphae. Scale bar = 10 μm. Drawings by Brian A. Perry.