The genus Lophium Fries
Syst. Myc.. II: 534 (1823)
by Eric W.A. Boehm
Lophidium Karsten 1873
The genus Lophium is characterized by carbonaceous conchate ascocarps, sometimes seated on a foot-like base (Zogg 1962), or sessile directly on the substrate. The thin-walled scleroparenchymatous peridium encloses a basal hamathecium of narrow trabeculate pseudoparaphyses, with very elongate asci, each bearing one fasicle of transversely septate filiform ascospores, often spirally arranged. The type species, Lophium mytilinum (Pers.) Fries, is cosmopolitan in the temperate zones and has been recorded from both sides of the Atlantic (Barr 1990; Zogg 1962). Zogg (1962) described two additional species, L. elegans Zogg on Juniperus from alpine regions of France, Italy and Switzerland, and L. mayorii Zogg on Pinus and Larix from the Swiss and French Alps, noting that L. mayorii differed from other species of Lophium in having rigid, band-forming ascomata. Vasilyeva recently (2001) found the same fungus in the Russian Far East and stated that it differed sufficiently from other species of Lophium in having gross, erumpent crowded ascomata, band- or ridge-like in appearance, as compared to the smaller, fragile, and entirely superficial fruitbodies typical of species of Lophium and made the transfer to Zoggium mayorii (Zogg) Vasilyeva (Vasilyeva 2001). Like the genus Mytilinidion, species within the genus Lophium have only been recovered from coniferous substrates. The sole exception is the recently described Lophium igoschinae Chlebicki recently recovered from Dryas octopetala and D. crenulata (Rosaceae) from Russia and Greenland (Chlebicki & Knudsen 2001).
In a recent molecular phylogenetic study, Boehm et al. (2009) were able to obtain two isolates of L. mytilinum from the United States (Michigan and New York), with 70 years separating their collection (see Table 1, below). We were also able to include in this study sequence data for the nuSSU and nuLSU from another L. mytilinum isolate from Sweden (CBS 114111) from GenBank (Table 1). Surprisingly, although these three isolates were in the same clade with species of Mytilinidion (Fig. 3, below), they did not show any particular connection to the scolecosporous species surveyed belonging to the subgenus Lophiopsis, once thought to form a transitional group to the genus Lophium (Lohman 1932b). Lastly, it was concluded that the genus Lophium actually preceded the genus Mytilinidion sens. lat. (Fig. 3), with the filiform spore preceding the phragmospore (Boehm et al. 2009).
Key to the species of Lophium
- Fruitbody erect, conchate, with thin-walled sclerenchymatoid peridium → 2
- Fruitbody conchate, but crowded, band- or ridge-like, horizontal to recumbent and elongated; ascospores arranged parallel in the ascus, measuring (60-)80-100(-110) x 3-4(-5) μm; Europe, Russian Far East → Lophium mayorii Zogg
Note: L. mayorii was transferred to the genus Zoggium (Vasilyeva 2001).
- Ascospores filiform, 12-15-septate, measuring 78-86 x 2.6-3 µm; on Dryas, Greenland, Russia → Lophium igoschinaeChlebicki
- Ascospores filiform, but longer; on conifers → 3
- Ascospores arranged parallel in the ascus; measuring (130-)170-250(-300) x 1-2(-2.5) μm; cosmopolitan →
Lophium mytilinum (Pers.) Fries
- Ascospores spirally arranged in the ascus; measuring (200-)260-280(-300) x 2 μm; Europe → Lophium elegans Zogg
Lophium mytilinum (Pers.) Fries
Fries, Syst. Myc.. II, 1823, 533-534.
Hysterium mytilinum Pers., 1801
Lophium mytilinellum Fries, 1823
Lophidium mytilinellum (Fr.) Karst., 1873
Common, cosmopolitan world-wide in coniferous forests (Europe & North America). Collected from bark & stems, dead wood & cones of Pinus, Larix, Picea, Abies & Juniperus.
Ellis & Everhart (1892): ” Sub-pedicillate, dilated above, transversely striate, shining black. Asci cylindrical, 140 – 160 x 9 – 10 μm with a short, thick stipe, eight-spored, with slender, septate, hyaline, branching paraphyses. Ascospores filiform, 120 – 140 x 1.5 – 2 μm, 18 – 20 guttulate, hyaline. On bark of Pine & Spruce. Generally arising from a black, effused, indeterminate crust in which the stipe is concealed. Fructifications fragile, of medium size. We have given the diagnosis of this species, though it is uncertain whether it has yet been found in this country.”
Lohman, M.L. (1933): “Fruiting abundantly on bark & exposed wood of dead branches of Pinus sylestrisL., & P. strobus L. Also on cones of P. ponderosa & on old stumps of Larix laricina. Collected in Sept. & Nov. Mature hysterothecia 0.4 – 0.7 x 0.1 – 0.5mm, the height equaling or exceeding the width; asci 150 – 190 x 7 – 8 μm; ascospores (120) 140 – 175 x 2 μm, yellowish hyaline, filiform & 18 – 20 septate. Anamorphic stages: dematiaceous hyphomycete Papulispora mytilina (Pers.) Lohman & coelomycetous pycnidia.”
Barr (1990): “Ascomata 500 μm to 1mm high & wide, laterally compressed, 200 – 300 μm wide in side view; peridium narrow. Asci 140 – 190 (-300) x 6 – 8 (-10) μm. Ascospores 120 – 175 (-300) x 1 – 2 μm, 18 – 20 septate. Anamorph coelomycetous: compound conidiomata (250-) 400 – 600 μm diam., one large or several small centra, opening by several papillate ostioles; conidiogenous cells short, (2.5-) 3 5 x 2 – 2.5 μm; conidia 1.5 – 2 (-2.5) s 1 – 1.5 μm, hyaline, oblong, one celled; hyphomycetous Papulasporabulbils 15 – 18 x 10 – 12 μm, coiled structures (Lohman, 1933). Distribution: On gymnosperms, north temperate zone (Finland, Canada, USA: Maine, Michigan, New Hampshire, Vermont on Abies balsamea & Juniperus. Note: The peridium of immature ascomata is two layered: the outer composed of small, dark, vertically oriented rows of cells, the inner composed of hyaline, transversely oriented rows of cells.”
Lophium mytilinum (Pers.) Fries. From Left: Zogg (1962). Photo credits: E.W.A. Boehm
Lophium mytilinum (Pers.) Fr. Photo credits: Alain Gardiennet.
Lophium elegans Zogg
Zogg, Ber. Schweiz. Bot. Ges. 64: 139-141. 1954.
Rare. Europe (Italy, Switzerland, Southern maritime France). Recently collected from near Dijon, France on living & dead Juniperus.
Ascomata upright, but with a less prominent stalk as compared to L. mytilinum. Ascospores very long scolecospores as L. mytilinum, but in ascus arranged in spiral parallel configuration. According to Zogg, the mature ascospores are actually part-spores, breaking up at maturity. The mature spores are slightly pigmented; a plae yellow, and measure ca. 1.5x larger than ascus when fully extended; spores measuring (200) 260 – 280 (300) x 2 μm. I have not observed the ascospores of L. elegans to become part-spores. Upon release they do assume a length longer than the ascus, but have not been observed to fragment.
Lophium elegans Zogg. Left: Zogg (1962). Photo credits: Alain Gardiennet. Note spiral arrangement of spores in the ascus, as compared to L. mytilinum.
Lophium igoschinae Chlebicki
Acta Societatis Botanicorum Polonniae 70: 295. 2001.
Chlebicki & Knudsen (2001): “Ascomata superficial, conchate, laterally compressed, surface black, irregularly granular or undulate, apex cristate with longitudinal slit covered by very small papillae, asci cylindric 90-97 x 8-9 μm, spores filiform, with obtuse ends, 12-15 sepate, pale yellow 78-86 x 2.6-3 μm, trabeculae sparse, filiform, simple or branched in lower part,, with thickended ends, in gelatinous matrix. Spores of the new species resemble those of L. mayori, but its apothecia are distinctly smaller. L. igoschinae is the first species of this genus which has been found on non-coniferous substrata”. Collected on the veins of lower and upper surface of dead leaves of Dryas octopetala from Russia, the Polar Ural Mts., and from Greenland, as well as from D. crenulata from the Tchukotka Peninsula, Russia.
Lophium igoschinae Chlebicki. From Chlebicki & Knudsen (2001).