Tricharina tophiseda, Matocec & I. Kusan, 2015

Kušan, Ivana, Matočec, Neven, Mešić, Armin & Tkalčec, Zdenko, 2015, Tricharina tophiseda-a new species from Croatia, with a revision of T. japonica (Pyronemataceae, Pezizales), Phytotaxa 221 (1), pp. 35-47 : 42-43

Comparison of Tricharina tophiseda and T. japonica

Microscopic analysis of living apothecia of T. tophiseda showed that this species is similar to T. japonica based on the very long marginal hairs (the longest in the genus) and size of the ascospores ( Yang & Korf 1985b). However, the ascospores of T. japonica were described as trapezoidal, a shape that was not observed in T. tophiseda . Therefore, it was necessary to examine the type material along with the European collection ( Dougoud & De Marchi 2012), which confirmed this character. Our examinations further showed that T. japonica differs from T. tophiseda in several important microscopic and macroscopic characters, summarised below ( Table 1).

Most notably, the ascospore length/width ratio in T. tophiseda is much lower than that seen in T. japonica ( Table 1). During the revision of T. japonica , 100 ascospores were measured from each dried collection to obtain statistically reliable sample sizes in order to discriminate between T. japonica and T. tophiseda using ascospore length and width. The analysis showed that spore length in T. japonica is slightly different than stated in the protologue, i.e. 16.4–21.5 μm rather than the initially reported 15.8–19 μm. Living ascospores from the recent collection of T. japonica (R.D. 31.01.245.11) were also measured for comparison with T. tophiseda . These measurements indicated that young and immature spores in T. japonica do not display larger spore dimensions, contrary to the observations in the protologue ( Yang & Korf 1985b). Instead, they are considerably smaller (14.4–17.4 × 6.2–8.3 μm), less refractive than mature spores, and possess an under-developed and thin spore wall.

The marginal hairs of T. tophiseda and T. japonica are similar, being straight, partly stiff and thick-walled, with strongly tapered apex in the longest hairs, but also with rounded apices in shorter hairs ( Fig. 1G–H , 2F–G , 3O ). However, the shape of the basal cell differentiate these two species, being sub-bulbous to bulbous in T. tophiseda vs. prismatic-truncate or rarely bulbous in T. japonica . In T. japonica , true excipular hairs were observed to extend down the whole excipular flank, which is an important but hitherto unreported feature ( Figure 3N ), while those of T. tophiseda are confined only on the upper excipular flank. The apothecial bases of both species are covered with hyphoid subicular hyphae with bulbous bases, but in T. japonica they are richly branched and occasionally anastomosed ( Fig. 3V ), while in T. tophiseda they are rarely branching and not anastomosing at all.

mm.

Both species are probably saprotrophs, living on different substrates in humid habitats. Tricharina tophiseda was found twice on a continuously wet tufa barrier (outside of an area with tufa-forming mosses), surrounded with scarce minute plant remnants, and shaded by Populus sp. , Fraxinus angustifolia , Platanus sp. and Ficus carica riparian vegetation. In contrast, the Swiss collection of T. japonica was found on bare sandy soil in a riparian forest with Quercus sp. , Fraxinus sp. , Alnus sp. and Corylus sp. ( Dougoud & De Marchi 2012). More precise ecological data for the type collection were not provided ( Yang & Korf 1985b). Cultural studies of T. tophiseda and T. japonica were unsuccessful from rehydrated apothecia on the same media that Yang & Korf (1985a) used in their ascorhizoctonia-type anamorph studies. The acidity of agar plates was pH 4 (more acidic than CYA pH 6.3 and MEA pH 5.3 used for inoculation from fresh apothecia of T. tophiseda ) which may have inhibited ascospore germination, especially for T. tophiseda which inhabits an alkaline tuffaceous substratum.

Figures

FIGURE 1. Tricharina tophiseda.A.Ascus apex with the ascospore.B.Ascus apex. C. Paraphyses.D.Ascus base with a part of ascogenous system. E–F. Ascospores (representing all shape variations). G. Marginal hairs apices and a middle part. H. Marginal hair fascicle. I. Excipular texture. A–E, G, I from (CNF 2/8079, holotype), C, F, H from (CNF 2/7953). All in *H O, except B is in *CR. Scale bars: A–F 2 = 10 μm, G, I = 50 μm, H = 100 μm. Del. N. Matočec.

FIGURE 2. Tricharina tophiseda. A–D.Living apothecia.E. Section through the apothecia. F. Marginal and submarginal area (side view). G. Margin. H. Paraphyses and ascospores (two lower ascosp. in early stage of germination). I. Asci with ascospores. J–K. Ascospores. L. Asci (each in a different focal view). M. Middle part of the marginal hair. N. Ascospores (with visible BSG). O–R. Cells in a meddulary excipulum.A–C, E–R from (CNF 2/8079, holotype), D from (CNF 2/7953). E–J, O in *H O, K in †KOH, L in *CR, M, R in *CRB-KOH, P 2 in *IKI. Scale bars:A = 5 cm, B–C = 2 cm, E–G = 200 μm, M, O–R = 20 μm, H–L, N = 10 μm. Phot. I. Kušan & N. Matočec.

FIGURE 3. Tricharina tophiseda—Colony and ascorhizoctonia-type anamorphic structures on CYA (A–J) and MEA (K–L). A. Germinating ascospores. B. Colony after 1 day. C. Colony rim after 2 days. D. Mycelial branching with the septal positions. E. Terminal and lateral nodules. F. Mycelial loops.G. Smooth and rough walled hyphae. H.Young moniliform sporodochia-like cell aggregates. I. Ripe moniliform sporodochia-like cell aggregates. J. Aerial hyphae (after 5.5 days). K. Hyphae preceding to formation of sporodochia-like cell aggregates. L. Moniliform sporodochia-like cell aggregates. T. japonica—Apothecia, ascospores and excipular structures (M–W). M. Part of the type collection. N. Section from the margin to the apothecial base (red arrow). O. Marginal hairs. P. LBs in the ectal excipular cells. R. Excipular hairs (side view). S. Excipular hairs with bulbous base (section). T–U.Ascospores.V. Subicular hyphae.W.Ascospores.A–L from (CNF 2/8079, holotype), M–O, R, T–V from (CUP-K-(JA-000286), holotype), P, S, W from (R.D. 31.01.245.11). D–K, W in *H O, 2 N–O, T, V in †KOH, P–S, U in †CB. Scale bars: B–C, M = 5 mm, N = 200 μm, J, O, R = 100 μm, S, V = 50 μm, A, H–I, P = 20 μm, D–G, K–L, T–U, W = 10 μm. Phot. I. Kušan & N. Matočec.