Epiphytic Crustose Lichens of the Clearwater Valley, British Columbia


Crustose lichens containing a trebouxioid alga, or parasitic on other lichens; thallus smooth, scurfy, areolate, or sorediate; apothecia jet black, or whitish pruinose in some species, with a prominent and persistent rim, or the rim receding with maturity, rarely with the thallus extending up the sides; exciple formed of tangled hyphae embedded in thick, usually deeply pigmented gel; hymenium pigmented in the upper half, formed of straight paraphyses that are embedded in gel only in the upper pigment layer; hypothecium usually pigmented; asci clavate, with a thickened, IKI+ medium blue tholus with a narrow axial mass that narrows near the tip; spores 8 per ascus, broadly elliptical to kidney-shaped, colourless, lacking septae.

References: Knopf & Leuckert 2004; Spribille 2006.

1a.Thallus C+ yellow-orange, UV+ yellow; spores 10-17 × 6-9  µ; common in some regions of BC, especially on the coast, to be sought …[Lecidella elaeochroma (Ach.) Hazsl.]
1b.Thallus C-, UV- or + bluish; spores various …2
2a.Thallus K-; spores 10-18 × 6-10  µ; apothecia lightly to heavily white-pruinose; occasional …“Lecidella laureri”
2b.Thallus K+ yellow; spores various; apothecia not pruinose …3
3a.Apothecia 0.3-1 (‑1.5) mm wide, with a thin, receding rim; spores 8-16 × 6-9  µ; upper hymenium blue-green to greenish brown (sometimes green tones very faint), K+ green or grey; disc black; hypothecium deep orangish brown; pycnidia absent …Lecidella euphorea
3b.Apothecia 0.5-1.7 (‑2) mm wide, with a thick, persistent rim; spores 10-18 × 6-10  µ; upper hymenium brown or grey-brown, lacking blue or green tones, K- or K+ pinkish; disc brown or black; hypothecium colourless or pale pinkish brown; pycnidia conspicuous, black, dome-shaped …Lecidella robusta ined.

Lecidella euphorea (Flörke) Hertel

Thallus whitish, grey, bluish grey or green, thin and smooth, or thickly warty, sometimes immersed, sometimes producing soralia; apothecia 0.3-1 (‑1.5) mm, jet black, matte or glossy, with a rim that is coloured like the disc and that may be prominent or inconspicuous, mostly receding with maturity, the disc flat or convex; rim non-algal, pale red-brown within, but darker at the edge, with blue-greenish or dark brown pigments; hymenium 70-90  µ high, lacking gel, colourless; upper hymenium dark blue-green, K+ greener; hypothecium medium to dark red-brown; paraphyses coherent only in the upper hymenium (apparently glued together by the epihymenial gel, freeing in K); asci usually broadly clavate; spores broadly elliptical, sometimes flattish on one side, or bean shaped, the walls 0.7-1.0 mm thick, thicker in K, 8-16 × 6-9  µ; pycnidia unknown.

Reactions: Thallus K- or K+ yellow or yellow-orange, C-, KC-, PD-.

Contents: Too complex to list here, but notably without granulosin and with thiophanic acid.

Habitat: Mostly on bark of Juniperus scopulorum, cottonwood and aspen (Populus), and in aspen drip-zones, less often on bark of Pseudotsuga outside dripzones. Lower elevations.

Similar Species: Lecidella is easy to recognize by the lack of a hymenial gel. The other species encountered in the study area differ unambiguously according to current taxonomic understanding by the spot tests or apothecial pigments.

Specimens: Björk 12334, 13778; Goward 94-889.

Local Status: Common.

Notes: Lecidella elaeochroma, L. euphorea and L. laureri are distinguished based on chemical characters foremostly, but spot tests do not seem to correspond cleanly to macro- and micro-morphology in our study area. The description given here is taken from the literature and may not fully apply to local material.

Lecidella laureri auct. non.

Thallus smooth or partly areolate or verruculose, scurfy, usually thick, white; apothecia 0.3-1 mm wide, black, but usually light to heavily pruinose, with a thin, receding rim, sometimes also with thalline material ascending up the side, the disc low-convex at maturity; hymenium dark blue-green in upper portions; hypothecium light to medium yellowish brown; spores 10-18 × 6-10  µ; pycnidia absent.

Reactions: All spot tests negative.

Contents: No known lichen substances.

Habitat: On high-pH bark, especially on Populus, or in Populus dripzones. Lower elevations.

Similar Species: The rather large, pruinose apothecia and occurrence on high-pH bark are diagnostic, and this species in not likely to be mistaken for any other in the study area.

Specimens: Björk 15150.

Local Status: Rare.

Notes: Lecidella laureri is based on the type of Megalaria laureri, which is not related. No name exists to replace L. laureri.

Lecidella robusta Björk ined.

Thallus smooth, cracked or areolate, thick, waxy whitish, grey or greenish grey; apothecia0.5-1.5 (‑2) mm wide, glossy, brownish black, with a thick, persistent rim, sometimes becoming compound; rim bluish-brown in the outermost layers, medium red-brown within, lacking crystals; hypothecium colourless; hymenium 75-90  µ high, colourless except medium to dark brown in upper portions, K+ pinkish, lacking crystals; spores 10-18 × 6-10  µ; pycnidia conspicuous, black, domed; conidiospores 20-25 × 1  µ, curved about 120-180 degrees.

Reactions: K+ yellow, C-, KC-, PD- or + pale yellow.

Contents: Unknown.

Habitat: On wood of a decorticated root of a Thuja tip-up mound. Lower elevation.

Similar Species: Mycoblastus sanguinarius appears similar at first glance, but does not have a well developed rim.

Specimens: Björk 10852.

Local Status: Rare.

Notes: The habitat suggests that this may be a normally saxicolous species, but no saxicole or muscicole species of Lecidella known in our study area accounts for the morphology of L. robusta. To date known only from the study area.