Lecanoropsis austrocascadensis Hollinger & Ivanovich, 2025

Ivanovich, Cristóbal, Weber, Lilith, Palice, Zdeněk, Hollinger, Jason, Otte, Volker, Sohrabi, Mohammad, Sheehy, Steve & Printzen, Christian, 2025, A taxonomic revision of the lichen genus Lecanoropsis (Lecanoraceae), Phytotaxa 695 (1), pp. 1-56 : 15-17

Lecanoropsis austrocascadensis Hollinger & Ivanovich , sp. nov. Fig. 4 .

MycoBank nº: 848532

Type:— U. S. A. California: Siskiyou Co., Mt. Shasta, just SE of jct. of Widow Springs Drive and Forest Service Road, 1650 m alt., 41.362° N 122.0855º W, 17 September 2016, J. Hollinger 15355 (FR-0183030!— holotype). Lecanomics Code: 985.

Diagnosis: Thallus poorly developed or endosubstratal; apothecia rounded, apothecial disc red-brown, epruinose, apothecial margin uneven and discontinuous in old apothecia, whitish yellow to almost concolorous with disc; producing pseudoplacodiolic acid.

Thallus endosubstratal, sometimes episubstratal, then thin and poorly developed, forming scattered small warts, whitish-grey. Photobiont a chlorococcoid/trebouxoid algae. Apothecia rounded, scattered, single to aggregated in small to large groups, appressed to sessile, (0.4–)0.43–0.47(–0.55) mm diameter. Apothecial disc flat to convex, red-brown to dark brown, glossy, epruinose. Apothecial margin when young, thick, smooth, even to irregular to crenulate, typically on level with the disc, sometimes weakly raised. Unevenly receding in old apothecia, (0.03–) 0.05 (–0.07) mm wide. Whitish-yellow but darkening to almost concolorous with disc. Amphithecium with golden-brown granules accumulating in the basal cortex and in the algal layer. Amphithecial cortex thin laterally, thicker at the base, gelatinized to heavily gelatinized at the base; (9–)12–17(–22) µm wide laterally, (25–)36–38(–56) µm wide basally, sometimes epihymenium pigmentation extending into the amphithecial cortex almost to the base. Parathecium thin, weakly protruding, in young apothecia conspicuous and observable as a ring of lighter coloration around the disc, becoming inapparent in older apothecia. Epihymenium hyaline to golden-brown to brown, containing Superba -brown. Hymenium hyaline, (35–)40–45(–55) µm. Subhymenial layers hyaline, (55–)60–85(–100) µm. Paraphyses usually simple, sometimes branching, rarely anastomosing, ca. 1.5–2 µm wide, apices not to weakly capitate, ca. 2–3.5 µm wide, gel sheaths at apices ca. 3–5 µm, some pigmented brown. Spores narrowly ellipsoid, simple, hyaline, (8.5–)9.5– 11(–12) × (2.6–)3.5–3.7(–4.3) µm. Conidia : Microconidia bacilliform, 4–6 × 1–1.5 µm; leptoconidia filamentous and curved, 18–20 × 1–1.5 µm, rare; macro- and mesoconidia were not found.

Chemistry: Pseudoplacodiolic acid (major).

Substrate: Lignicolous, on decorticated branches of Abies concolor and Pseudotsuga menziesii .

Ecology: In dry conifer or mixed oak-conifer forests between 900 to 1650 m alt.

Distribution: Southern Cascade Mountains in Northern California, U.S.A.

Notes: Lecanoropsis austrocascadensis may be difficult to determine and was only detected as a separate species after examination of the DNA sequences. Lecanoropsis austrocascadensis apothecia have an appearance similar to epruinose ones of L. subravida . However, L. subravida produces usnic acid as major and sometimes also pseudoplacodiolic acid, whereas pseudoplacodiolic acid is the only secondary metabolite so far detected for L. austrocascadensis . In addition, L. austrocascadensis has smaller apothecia [(0.4–)0.43–0.47(–0.55) mm] and narrower spores [(2.6–)3.5–3.7(–4.3) µm] than L. subravida .

Apothecia of L. austrocascadensis may be similar in colour to epruinose ones of L. saligna , but L. saligna produces isousnic and rarely usnic, but not pseudoplacodiolic acid, on average has wider spores [(3.0–) 4.0–6.0(–7.5) µm] and longer microconidia (7.5–10 × 1 vs. 4–6 × 1–1.5 µm in L. austrocascadensis )

Lecanoropsis sarcopidoides and L. austrocascadensis are the only species of Lecanoropsis with pseudoplacodiolic acid as major secondary metabolite. However, the apothecia of L. sarcopidoides have usually a conspicuously coarse bluish-white pruina and its spores are slightly smaller [(6.0–)7.2–9.5(–10.0) × (2.5–)3.2–3.6(–4.5) µm)] than those of L. austrocascadensis .

Lecanora austrocascadensis may also resemble old L. subintricata , but apothecia of L. subintricata produce paler discs with more greyish tones, and have a characteristic smooth yellow margin when young. Both also differ in chemistry, as L. subintricata produces usnic acid. Another Lecanoropsis species that can resemble L. austrocascadensis is L. omissa , yet L. omissa has in general smaller (0.2–0.4(–0.7) mm), paler apothecia with fine white pruina and a smoother and even margin. In addition, the amphithecial cortex is more gelatinized laterally (not as extreme, however, as in L. subintricata or L. sarcopidoides ) and hyaline, and it produces usnic instead of pseudoplacodiolic acid.

Etymology: Latin for “from the southern Cascades” in reference to its occurrence in the Cascade Range.

Additional specimen studied: U.S.A. California; Shasta Co., Lake Britton, just S of Hwy. 89 at top of slope W of bridge over lake, 900 m alt., 41º00’54” N 121º37’55.2” W, 16 September 2019, J. Hollinger 15452 (FR-0183029). Lecanomics Code: 986 .

Figures

FIGURE 4. Lecanoropsis austrocascadensis. A, habitus. B, apothecial section in LCB. All from U.S.A., California, J. Hollinger 15355 (FR-0183030; L985). Scales:A = 500 µm; B = 20 µm; C & D = 10 µm.