Coprotus sexdecimsporus (P. Crouan & H. Crouan) Kimbr. & Korf, American Journal of Botany 54(1): 22, 1967.

Kusan, Ivana, Matocec, Neven, Jadan, Margita, Tkalcec, Zdenko & Mesic, Armin, 2018, An overview of the genus Coprotus (Pezizales, Ascomycota) with notes on the type species and description of C. epithecioides sp. nov., MycoKeys 29, pp. 15-47 : 21

Coprotus sexdecimsporus (P. Crouan & H. Crouan) Kimbr. & Korf, American Journal of Botany 54(1): 22, 1967. Fig. 3

≡ Ascobolus sexdecimsporus P. Crouan & H. Crouan, Annales des Sciences Naturelles Botanique ser. 4., 10: 195, 1858.

≡ Ascophanus sexdecimsporus (P. Crouan & H. Crouan) Boud., Annales des Sciences Naturelles Botanique ser. 5., 10: 247, 1869.

≡ Ryparobius sexdecimsporus (P. Crouan & H. Crouan) Sacc., Sylloge Fungorum 8: 541, 1889.

Description.

Apothecia not confluent, circular from the top view, at first globular, then flattened-turbinate and finally lenticular from the side view, sessile, evenly hyaline to creamy white or translucent pale greyish-rosy (if subjected to strong insolation), glabrous, *0.1-0.5 mm in diameter, solitary to gregarious. Hymenium granulose due to the protrusion of living mature asci, concolorous with excipular surface, matte. Margin rounded in vertical median section, entire, smooth, not raised above hymenial plane. Outer surface smooth, concolorous with the hymenium. Subicular hyphae indistinguishable. Hymenium *95-140 µm thick. Asci clavate with truncate apex, *84-143 × 21.4-29.6 µm, †89-104 × 16.4-23.3 µm, *Q = 4.1-5.6, significantly shorter and more clavate at the marginal rim, when mature *protruding above hymenium up to 26 µm, pars sporifera*47.3-63.3 µm, 16-spored, hyaline, base attenuated, bifurcate, arising from perforated croziers, only fully mature asci with flat lentiform operculum clearly delimited prior the spore discharge, *6.6-8 µm in diam. and *0.6 µm thick, lateral wall 3-layered, *0.7-0.8 µm thick, after spore discharge operculum as a rule clearly visible; in IKI inamyloid; in CR outermost wall vividly rutile-red throughout the ascal length, median layer pale rutile-yellow, innermost layer greyish; in CB cyanophobic. Ascospores *10.7 –11.7– 13.8 × 6.8 –7.9– 8.5 µm, *Q = 1.4 –1.7– 1.7, ellipsoid to narrowly ellipsoid and most often radially symmetrical, with rounded-obtuse poles, rarely slightly bilaterally symmetrical with one side somewhat less convex but never flattened, 1-celled, hyaline; in living asci bi- to triseriate; when freshly ejected remain in a single group for a while due to the delicate sticky sheath enveloping individual spores; surface smooth; wall 3-layered, 0.6-0.7 µm thick, perispore dull, epispore brightly refractive, endospore layer with pale greyish-isabelline refractivity; in IKI no notable differential stainings; eguttulate, uninucleate, nucleus ± centrally to unipolarly positioned, 2.7-3 µm wide, in CRB nucleus and sheath more contrasted, perispore dull deep bluish-violet/deep cyan, epispore CRB-, endospore purplish lilac/medium violet; after applying KOH spore sheath dissolves instantly, all structures discoloured, perispore not loosening, endospore layer purplish-rosaceous; in CR perispore dull, not stained as epispore, but endospore lilac reddish; in AC completely devoid of staining; in CB de Bary bubbles present only in mature spores, perispore not loosening, weakly cyanophilic. Paraphyses cylindric, apically obtuse to subclavate, always slighty bent to uncinate, densely septate, rarely simple but often richly branched in the upper part; apically producing abundant medium to strongly refractive golden-yellow to cinnamon-yellow granular exudate, in IKI copper orange, in CRB dark grey blue, after applying KOH rubis red-grey; apical cells *6.9-16.4 × 2-3.4 µm, †1.4-2.8 µm wide, wall thin and hyaline, cells in the upper half contain minute medium to strongly refractive hyaline globules *0.2-1 µm wide or in pigmented apothecia with beer-yellow to beer-orange scattered dotted granules which are in IKI greyish green, in CRB deep purplish-lilac to deep violet; in CB wall cyanophobic, cytoplasm weakly cyanophilic. Subhymenium only slightly differentiated from medullary excipulum, *12-19 µm thick, composed of hyaline textura globulosa-angularis, cells *3.8-7.5 µm wide. Medullary excipulum hyaline, in the middle flank *12-22 µm thick, composed of textura porrecta, cells runing parallel to the surface, *1.4-4.8 µm wide. Margin subhyaline, fairly reduced to a thin cellular zone *9.6-11.3 µm thick at ½ of hymenium height, composed of small celled textura angularis 1-2 cell thick, cells clavate or elongated angular, 2.4-8.8 µm wide, marginal rim composed of prismatic terminal cells which do not protrude above hymenium; in CB cell walls strongly cyanophilic. Ectal excipulum hyaline, in the middle flank *48-56 µm thick, composed of textura globulosa, cells *7.2-16 µm wide, walls yellowish; in IKI some cells with visible moderate accumulations of glycogene; in CB cell walls slightly cyanophilic; in AC cell walls and cytoplasm deeply lilac. Overall excipulum devoid of crystalline matter, without colouring in KOH, in IKI completely inamyloid. Anamorph not found.

Distribution and ecology.

The species has a cosmopolitan distribution and can be found on dung of various wild and domestic animals, mainly herbivores (especially ruminant animals and rodents). In the temperate zone it is distributed in the habitats from maritime to alpine zones.

Specimens examined.

CROATIA. Zadar County, Island of Dugi Otok, Velo jezero area, 5 km W from Sali, 43°56.46'N; 15°06.00'E, 5 m a.s.l., on dung of Equus asinus , 1 Jun 1998, N. Matočec (CNF 2/3806); Split-Dalmatia County, Island of Vela Palagruža, 70 m E-NE from the lighthouse, 42°23.58'N; 16°15.38'E, 60 m a.s.l., on dung of Equus asinus , 29 Mar 1999, N. Matočec (CNF 2/4200); Dubrovnik-Neretva County, Koprendol area, 7.5 km N-NE from Metković, 42°59.30'N; 17°37.44'E, 130 m a.s.l., on dung of Ovis aries , 5 Mar 2001, N. Matočec (CNF 2/4928); Dubrovnik-Neretva County, Peninsula Prevlaka ( Oštra), 4.8 km N-NW from Vitaljina, 42°24.22'N; 18°30.53'E, 25 m a.s.l., on dung of Equus asinus , 31 Dec 2009, I. Kušan and N. Matočec (CNF 2/8394); Lika-Senj County, Sjeverni Velebit National Park, northern part of the Mt. Velebit, 280 m SW from the Vučjak peak (1644 m), 44°48.83'N; 14°58.46'E, 1550 m a.s.l.; on dung of Lepus europaeus , 11 Jun 2011, N. Matočec and I. Kušan (CNF 2/8942).

Notes.

De Sloover (2002) summarises the data on the distribution of pigments in microscopic elements in the Coprotus species described up to that time. His overview suggests that paraphyses are not the only cause of the overall apothecial pigmentation. However, our detailed study on living material of C. sexdecimsporus over a period of two months clearly showed that cytoplasmic pigments in the paraphyses develop with exposure to light. These observations used apothecia on original substrate and were carried out under controlled conditions. The pigments developed under sunlight or artificial light with a sufficient amount of the ultraviolet wave-length. On the other hand, pigmentation was completely absent if apothecia were grown continually under dark or low-light conditions. There is considerable variability in ascospore dimensions given in the literature. Although it seems that ascospore length may vary regardless of any presently visible cause, the ascospore diameter seems to be smaller in material from the Southern Europe / Mediterranean region. Accordingly, material from Italy ( Doveri 2004) and Tunisia ( Häffner 1996), almost completely overlap with our studied material from the East Adriatic region. These are in the range of ascospore widths from 6.9-8.5 μm. Specimens from the European Atlantic ( Crouan’s material restudied by Le Gal, 1960), Norway (Aas, 1983) and both Americas ( Kimbrough et al. 1972, Dokmetzian et al. 2005) have spores with greater spore widths, ranging from 7.5-10 μm. These differences might point to some ecological-geographical causes. The type material is missing according to Kimbrough et al. (1972).