Xylopsora canopeorum Timdal, Reese Naesborg & Bendiksby

Bendiksby, Mika, Naesborg, Rikke Reese & Timdal, Einar, 2018, Xylopsoracanopeorum (Umbilicariaceae), a new lichen species from the canopy of Sequoiasempervirens, MycoKeys 30, pp. 1-15 : 6-9

Xylopsora canopeorum Timdal, Reese Naesborg & Bendiksby sp. nov. Fig. 2

Diagnosis.

The species differs from X. caradocensis and X. friesii mainly in forming more minute, coralloid and sometimes, sorediate squamules and sometimes (the holotype) in containing thamnolic acid in addition to friesiic acid; it also differs from the former in having shorter, non-septate ascospores.

Type.

USA, California, Santa Cruz Co., 75 m E of North Escape Road, 125 m S of the third gate on North Escape Road in Big Basin Redwoods State Park, 37°10'46"N, 122°12'58"W, 341 m alt., on bark of main trunk more than 100 cm diameter, from the upper trunk of old Sequoia sempervirens in old-growth redwood forest, fall (autumn) 2015, R. Reese Næsborg 1522 (JEPS, holotype [TLC: friesiic acid (major), thamnolic acid (submajor); GenBank: MG309307 (ITS), MG309311 (mtSSU)]).

Description.

Thallus crustose to squamulose; individual squamules up to 0.5 mm diam. but often soon breaking up into a coralloid crust, adnate when young, later ascending and more or less geotropically imbricate; soralia occurring patchily, labriform, bluish; upper surface greyish-green to medium brown, dull; margin crenulate or incised, concolorous with upper surface. Upper cortex up to 15 μm thick but mostly poorly defined. Apothecia common, up to 0.6 mm diam., plane, black, epruinose, egyrose; margin remaining prominent, entire or flexuose; proper exciple composed of closely conglutinated hyphae, olivaceous brown in inner part, brownish black in the rim, not containing crystals, K–, N–; hymenium ca. 50 µm high, pale olivaceous brown; hypothecium pale olivaceous brown; epihymenium dark reddish brown, not containing crystals, K–, N–; paraphyses ca. 2 µm thick, simple, without swelling or pigment cap in apical cell; ascus clavate, ca. 30 µm tall, with a thin, evenly amyloid tholus and covered by an amyloid cap, with orange pigment in the cytoplasm when young. Ascospores ellipsoid, simple, hyaline, with orange pigment in the cytoplasm when young, 4-7 × 2.5-4.5 μm (n = 20, from holotype). Pycnidia not seen.

Chemistry.

Friesiic acid (major) and thamnolic acid (absent to submajor). Thallus PD– or PD+ yellow, K– or K+ yellow, C–, UV+ bluish white.

Distribution.

Specimens were collected from central coastal California in Big Basin Redwoods State Park (37.1°N, 11 km from the Pacific Ocean) and Armstrong Redwoods State Natural Reserve (38.3°N, 18 km from the Pacific Ocean).

Ecology.

Xylopsora canopeorum was observed on coarse, fibrous bark and occasionally on charred bark between 5 and 75 m above ground level along the trunks of large coast redwood trees in old-growth redwood forests. The species commonly co-occurred with Carbonicola anthracophila , Fulgidea oligospora , F. sierrae , Hertelidea botryosa and Hypocenomyce scalaris , which together covered substantial portions of the trunk surface. Xylopsora canopeorum appeared to have an affinity for old and stable bark surfaces on the main trunks of large redwood trees.

Etymology.

The specific epithet " canopeorum " refers to the habitat in which the species was encountered ¾ in the canopy of old-growth redwood forests.

Remarks.

The species differs from X. caradocensis and X. friesii morphologically by forming more minute squamules (less than 0.5 mm diam.) which soon break up into a coralloid crust and sometimes into soralia. In X. caradocensis and X. friesii , the squamules are up to 1.0 (-1.5) mm diam. and always esorediate. In the former, the squamules are bullate or irregularly ascending; in the latter more or less plane, adnate or somewhat ascending ( Timdal 1984). In X. caradocensis , the ascospores are longer (6.5-14 × 2-4 μm) than those of X. canopeorum and often 1- or 3-septate; in X. friesii , the ascospores hardly differ (4.5-7.5 × 2.5-3.5 μm) from those of X. canopeorum . Xylopsora caradocensis and X. friesii contain friesiic acid only ( Timdal 1984, as " friesii unknown").

In the current Californian lichen checklist ( Tucker 2014), Lecidea xanthococcoides Zahlbr. is the only species unknown to the authors that could be assumed to be an earlier name for X. canopeorum . That species was described from conifer trunks at 1700 m alt. in the San Bernardino Mountains, i.e. in an area and habitat where X. canopeorum possibly can occur. The holotype (H.E. Hasse 705) was not found in W upon enquiry. Details in the original description ( Zahlbruckner 1900) indicate that it is a different species, however - Apothecia becoming convex and immarginate, hymenium 160-180 μm high and ascospores 12-15 × 5.5-6 μm.

Additional specimens examined.

USA. California. Santa Cruz Co.: label data as for holotype, R. Reese Næsborg 1544 (NY); 800 m WNW of North Escape Road up Rodgers Creek in Big Basin Redwoods State Park, 37°11'44"N, 122°13'34"W, 403 m alt., on bark of branch less than 50 cm diameter in the lower crown of an old Sequoia sempervirens tree in an old-growth redwood forest, spring 2015, R. Reese Næsborg 1597 (O L-1315); 400 m E of North Escape Road along Sequoia Trail in Big Basin Redwoods State Park, 37°11'13"N, 122°12'54"W, 422 m alt., on bark of trunk more than 100 cm diameter in the upper trunk of an old Sequoia sempervirens tree in an old-growth redwood forest, Fall 2015, R. Reese Næsborg 1707 (O L-1316). Sonoma Co.: 50 m SW of Colonel Armstrong Tree parking area in Armstrong State Natural Reserve, 38°32'13"N, 123°00'29"W, 49 m alt., on bark from the upper trunk of an old Sequoia sempervirens tree in an old-growth redwood forest, fall 2015, R. Reese Næsborg 1775 (JEPS).