Gyromitra persicula Dirks & Beug

Dirks, Alden C., Beug, Michael W., Methven, Andrew S., Miller, Andrew N. & James, Timothy Y., 2024, Gyromitra persicula sp. nov. (Discinaceae, Pezizales), a novel discoid Gyromitra from Northwestern North America, Phytotaxa 644 (1), pp. 49-55 : 53

Gyromitra persicula Dirks & Beug , sp. nov. ( Fig. 2 )

MycoBank MB852786

Holotype: — USA. Washington: Klickitat Co., Mount Adams Horse Camp , 46.0515 -121.5357, growing from the ground, 30 May 2022, leg. Michael W. Beug, ACD0548, iNaturalist #119742009 (HOLOTYPE MICH346504 ; ISOTYPE ILLS00122612 ). Sequences: PP051296 (ITS), PP051288 (LSU).

Diagnosis:— Gyromitra persicula and G. leucoxantha are readily distinguished from other Discinaceae species by the scooped out “fishtail” apiculi of the mature ascospores. These two closely related taxa are separable by their size and coloration: G. persicula is small (up to 4.5 cm wide) and has a pinkish buff color, whereas G. leucoxantha is larger (up to 10 cm wide) and has an egg yolk yellow to yellow ochre color.

Description: —Ascomata consisting of a discoid hymenophore and pseudostipe, width 1.5–4.5 cm; hymenium buff to peach, smooth, becoming wrinkled; sterile underside off-white, drying tan, minutely pubescent; pseudostipe if present 1 × 1 cm. Medullary excipulum a textura epidermoidea. Paraphyses cylindric, apices subclavate, apical width 6.3–8.5 µm (W m = 7.4 µm), thin-walled, septate, unbranched, contents golden-brown in KOH. Asci 380–450 µm × 22–25 µm, cylindric, thin-walled, hyaline, eight-spored. Ascospores 36–44 µm × 16–19 (L m = 40 µm, W m = 17 µm, Q = 2.1–2.5, Q m = 2.3), ellipsoid, with a large central guttule and a varying number of smaller polar guttules, hyaline in KOH, inamyloid. Perispore present, expanded up to 2 µm in KOH, less noticeable in water, appearing minutely roughened due to a fine reticulation when mature (best observed in water or Melzer’s reagent), forming blunt apiculi with concave depressions enlarged in KOH, 3.2–4.9 µm × 6.7–8.9 (L m = 4.0 µm, W m = 7.8 µm).

Etymology: —From the Latin persica meaning peach along with the diminutive suffix - ula, referring to the peach coloration and small size, hence the common name “mini peach pig’s ears”.

Habitat and distribution: —Growing from soil in association with conifers in Washington, 250–1300 m elevation.

Additional specimens examined: — USA. Washington: King Co., Middle Fork Snoqualmie Natural Area , 274 m, 47.4922 -121.6411, in a mixed conifer forest, 3 June 2011, leg. Michael W. Beug ( MWB), ACD0515 ( MICH346493 ) ; Klickitat Co., Gotchen Creek Trail, 46.0880 -121.4929, growing from the ground in a mixed conifer forest, 9 June 2011, leg. MWB, ACD0526 ( MICH346499 ) (immature) ; ibid., 46.1069 -121.5075, in a mixed P. menziesii forest, 21 June 2011, leg. MWB, ACD0521 ( MICH346500 ) (immature) ; Klickitat Co., Mount Adams Horse Camp , 46.0499 -121.5327, 8 May 2022, leg. MWB, ACD0508 , Mushroom Observer #491382 ( MICH346505 ) (immature) ; Klickitat Co., Trout Lake , 46.0093 -121.5553, growing from the ground in a mixed conifer forest, 1 May 2005, leg. MWB, ACD0524 ( MICH346515 ) ; ibid., 46.0212 -121.5295, on soil, 30 May 2022, leg. MWB, ACD0552 , iNaturalist #119741787 ( MICH346513 ) (immature) ; Pierce Co., Mt. Rainier National Park , 46.7586 -121.5569, growing from the ground in an old growth forest, 17 May 2014, leg. MWB, ACD0525 ( MICH346519 ) ; Skamania Co., Trout Lake , 45.9688 -121.6573, growing from the ground, 13 June 2022, leg. MWB, ACD0547 , iNaturalist #121904369 ( MICH346523 ) .

Notes: —While separable by macromorphology, other distinguishing features of Gyromitra persicula and G. leucoxantha may be the degree of ascospore reticulation and prominence of the scooped-out apiculi in water. Whereas G. persicula shows a notable but somewhat faint ascospore reticulation, McKnight (1969) described the ascospores of G. leucoxantha as “very distinctly and coarsely reticulate”. We also observed a somewhat more pronounced reticulation in the one specimen of G. leucoxantha with mature ascospores that we studied ( Fig. 2 ). The ascospores of both taxa differ in appearance according to the mounting medium ( McKnight 1968). In water, the scooped-out apiculi of G. persicula could be overlooked but are prominent in KOH due to the expansion of the perispore, resulting in an overall increase in size of 10–15 %. In contrast, the scooped-out apiculi of G. leucoxantha are more obvious in water and are less likely to be overlooked. Discinaceae species mature over an extended period and are often inadvertently collected in an immature state when their ascospores have not yet attained their full size, ornamentation, and apiculi. More observations of ascospores from fresh deposits (i.e., living ascospores) are required to delineate these finer microscopic details and to establish a uniform comparison across the discoid Gyromitra ( Karakehian et al. 2021) .

Figures

FIGURE 2. Ascomata and microscopic features of Gyromitra persicula (A–G) and ascospores of Gyromitra leucoxantha (H–I). A. Ascomata of the holotype collection (MICH346504). B. Peach-colored ascoma (MICH346523). C. Hymenium and excipulum (MICH346493). D. Asci and paraphyses with brown contents in KOH (MICH346493). E. Medullary excipulum of textura epidermoidea (MICH346493). F. Ascospores at various stages of maturity; note the blunt apiculi with a concave depression, large central guttule, and minute ornamentation (MICH346519). G. Close up of ascospores showing the pronounced “fishtail” apiculi and fine reticulation (MICH346519). H–I. Ascospores of Gyromitra leucoxantha (MICH25407); similar to those of G. persicula but with a more pronounced reticulation. Mounting medium: 5% KOH (C–D), 5% KOH stained with phloxine B (E–F, leftmost ascospore in G, H), Melzer’s reagent (two rightmost ascospores in G, I). Scale bars: 2 cm (A), 0.5 cm (B), 100 µm (C), 50 µm (D–F, H), 10 µm (G, I).