Montana Field Guide

GROWTH FORM: Crustose

THALLUS: Often not present or is poorly developed. When present thallus mainly grows within the wood (endosubstratal: upper lithocortex of fungal hyphae and wood, central layer of algae, and lower layer of fungal hyphae embedded in the wood). When present, the thallus occurs around apothecia, is smooth to verrucose, and beige to dark brown. Source: Ivanovich et al. 2025

PHOTOBIONT: Green algal - in the genera Chlorococcum or Trebouxia. Algal layer appears brighter-green. Source: Ivanovich 2025

REPRODUCTIVE TYPE: Apotheciate. Apothecia very abundant, sometimes completely covering the substrate; round, sometimes deformed shaped, normally sessile, rarely appressed, and (0.45-)0.50 – 0.67(-0.70) mm in diameter. Apothecial Disc is flat to weakly convex, ochre to reddish or dark brown, rarely weakly glossy, and typically not pruinose (epruinose); it is uncommon to have a fine to coarse white pruina. Apothecial Margin is whitish greyish to slightly darkening into beige. When young, the margin is thick, raised, and smooth to subrugose. When older, the margin may unevenly recede and form warts, becomes thinner, subrugose, and is (0.02-)0.04-0.08(-0.12) mm wide. Source: Ivanovich et al. 2025

CHEMICAL REACTIONS: Applied to cross-sections of the hymenial layer under a compound microscope. In water, epihymenial pigment color is hyaline to faint golden-brown to brown.
* Potassium hydroxide (KOH; K) reaction turns to orange-brown; a subsequent application of hydrochloric acid (HCL) turns to faint orange; another subsequent application of K turns yellow-orange to brown.
* Nitric acid (HNO3;N) reaction turns to orange-red; subsequent application of K turns to yellow-orange; subsequent application of HCL turns to faint orange; another subsequent application of K turns yellow-orange to brown. Source: Ivanovich et al. 2025

TAXONOMY & NOMENCLATURE
A systematic revision of the Lecanora saligna-group led to the resurrection of Lecanoropsis M. Choisy ex Ivanovich and descriptions for 23 species, of which 6 are new to science (Ivanovich et al. 2025). The revision is based on morphology and a phylogenetic analysis using 7 loci. Lecanoropsis iapyx was determined to be a new species to science. The formal description of this new species is based on the specimen (type) collected in Montana in 2016. Previously, specimens were lumped with L. saligna.

Lecanoropsis was originally described by Choisy in 1949, stating that the lichen “differs from the current genus Lecanora subgenus Eulecanora by the ovoid-oblong, straight or sometimes slightly curved pycnoconidia”. Into Lecanoropsis Choisey lumped Lecanoropsis saligna and three other species. However, Choisy’s work was considered invalid because the formal diagnosis was only provided in French; that is, the proper protocol for naming species was not followed. The recognition of Lecanoropsis M. Choisy was ignored until 1984. Hafellner (1984) doubted the validity of this ‘new’ genus, but applied the name to specimens he named Lecanoropsis saligna (Schrader) M. Choisy (lectotype). Hafellner (1984) stated that the pycnidia of Lecanoropsis saligna should be re-evaluated to determined if they truly differ from Lecanora s. str. in shape and size. In 2019, studies by Kondratyuk et al. put additional species into Lecanoropsis but failed to provide a formal description. Studies by Ivanovich et al. (2025) concluded that Lecanoropsis does warrant recognition based on molecular evidence and phenotypic traits, and chose to resurrect and properly describe the genus, and its members of species.

The specific epithet of iapyx is the name of a minor Greek wind god of the north-west or west-north-west wind (Ivanovich et al. 2025; Wikipedia 2025). The name refers to the lichens’ position within its distributional area of western North America (Ivanovich et al. 2025).

A Taxonomic Revision of the Lichen Genus Lecanoropsis (Lecanoraceae) by Ivanovich et al. (2025) should be consulted to identify the species and related taxa. This publication provides a dichotomous key for Lecanoropsis, detailed descriptions, photographs, and other information.

Lecanoropsis iapyx has a thallus that is typically endosubstratal; an apothecial disc of ochre to dark brown color and is flat to weakly convex; an apothecial margin that is whitish, thick, and becoming unevenly excluded, but persistent in old apothecia; macroconidia are reniform; and the thallus produces isousnic acid (Ivanovich et al. 2025).

Lecanoropsis iapyx is similar to Lecanoropsis saligna, a European species (Ivanovich et al. 2025). They differ in their conidia shape, by an epihymenial pigment reaction, and chemistry. The conidia in Lecanoropsis iapyx are reniform macroconidia with obtuse tips. The conidia in Lecanoropsis saligna are crescent-shaped with acute tips.

Lecanoropsis iapyx grows on conifer wood that is stripped of bark (lignicoleus), wooden planks, and fence posts (Ivanovich et al. 2025). It commonly occurs in oak and pine woodlands in semi-open areas. In Oregon, this lichen has also been found on fence posts in heavily grazed open pastures (Ivanovich 2025). The species has been found at elevations from 2625 to 8202 feet above sea level (800 and 2500 meters) (Ivanovich et al. 2025).

In Montana, Lecanoropsis iapyx was found within a Ponderosa Pine-Juniper woodland with calcareous sandstone outcrops, and on conifer wood of trees situated within a ravine.

CHEMICAL COMPOUNDS
Lichens produce primary and secondary chemical compounds that provide a variety of essential and specialized roles (McCune and Geiser 2023). Readers are encouraged to consult Nash (1996) and McCune and Geiser (2023) for more information.

Major compound found in Lecanoropsis iapyx is isousnic acid (Ivanovich 2025).

Sexual and asexual reproduction of the fungus occurs by macroconidia and spores produced from an apothecium.

SYMBIOTIC PROPAGULES
Conidium (-ia, plural) are found in some types of fungi; a spore produced asexually at the tip of a specialized hypha (-ae, plural) (Budel and Scheidegger in Nash [ed.] 1996). Lecanoropsis iapyxproduces conidia on specialized hyphae within pycnidia, which are embedded flask-shaped structures. Type of conidia produced are macroconidia, reniform in shape and 7-8.5 by 1.5-3 micrometers; other types of conidia are now known (Ivanovich et al. 2025).

GENERATIVE REPRODUCTION
Apothecia are disk-shaped fruiting bodies which hold the production of spores, from sexual reproduction of the fungus (Budel and Scheidegger in Nash [ed.] 1996). For technical guidance on identifying Lecanoropsis iapyx, readers should consult the full publication by Ivanovich et al. 2025. The margin of the apothecium (amphithecium) is usually filled with algae and interspersed with golden-brown granules. The amphithecium cortex is under-developed, sometimes without cortex, and moderately gelatinized, (8-)11-20(-28) micrometers laterally wide, (8-)13-20(-28) micometers basally side, hyaline. The parathecium is not distinguishable. Epihymemium is usually golden-brown possibly containing Leptocline-brown; usually with thick epipsamma of golden-brown granules that dissolve in KOH; rarely hyaline. Hymenium is hyaline, heavily inspersed with golden granules (35-)40-5(-55) micrometers. Subhymenial layer hyaline, (65-)95-135(-155) micrometers. Paraphyses rarely branching and anastomosing, segments short and stout in appearance, about 1.5-1.7 micrometers wide; apices not to weakly capitate, 1.7-1.7 micrometers; and apical gel sheaths, about 3.5 micrometers wide.

Spores ellipsoid, simple, hyaline (6.0)9.0-11.0(13.5) by (3.0)3.5-4.0(4.5) micrometers.

TYPE SPECIMEN
New botanical species are named and described based on a single specimen, which is designated as the name-bearing "type" and preserved in a herbarium. The species is formally accepted when named and described in a scientifically recognized publication. The specimen collected by lichenologist Bruce McCune in 2016 on a private ranch in Mussellshell County, Montana is the Type specimen used by Cristobal Ivanovich to formally describe Lecanoropsis iapyx (Ivanovich et al. 2025). In 2016, McCune also collected a second, duplicative specimen. The duplicate collection is referred to as the "isotype specimen" and is preserved at the University of Montana Herbarium (MONTU), Missoula, Montana.

As of 2025, there are no known threats to the population in Montana.