(S. Schatz) Whalley, E.B.G. Jones, K.D. Hyde & Læssøe


Sordariomycetes, Subclass Xylariomycetidae





Synonymy: ≡ Hypoxylon oceanicum S. Schatz, Mycotaxon 33: 413 (1988)

Sexual morph: Pseudostromata 0.4-0.8 mm diam., seated on decorticated wood, occasionally embedded at the base, pulvinate to hemispherical, single, in clusters of up to 30 uni-peritheciate pseudostromata, linear to suborbicular, surface leathery in fresh material, at maturity black, generally with conspicuous ascomatal projections. In section pseudostromata comprising host cells filled with light brown fungal cells in the form of textura globulosa or amorphous black fungal material. Ascomata immersed in pseudostroma, subglobose to hemispherical, soft to leathery, black, ostioles papillate.  Paraphyses 2-2.5 μm wide at the base, abundant, persistent, remotely septate. Peridium 25-35 μm wide, two layered, composed of an outer layer of cells of textura angularis and an inner layer of elongated cells. Asci 177-219 × 17-23 μm, eight-spored, cylindrical, unitunicate, subapical apparatus dark blue in Melzer’s reagent, tapering with a distinct apical rim, (4.7-)5.6-6.6 × 4.2-4.7 μm. Ascospores (17.9-)18.7-26(-28) × 7.5-13(-13.5) μm, uniseriate to obliquely uniseriate or partially biseriate at the upper end of the ascus, dark grey-olive to opaque brown, more or less inequilaterally ellipsoid, upper end broadly rounded, lower end slightly pointed, one-celled throughout ascospore development, bi-guttulate, wall smooth and relatively thick, without appendages or loosening perispore, germination slit usually clearly seen on the ventral side, straight, conspicuous, ½-¾ total length of spore. Asexual morph: undetermined.

Key references:

Li GJ, Hyde KD, Zhao EL, Hongsanan S, Abdel-Aziz FA, Abdel-Wahab MA, Alvarado P et al. (2016) Fungal diversity notes 253–366: taxonomic and phylogenetic contributions to fungal taxa. Fungal Diversity (**). DOI 10.1007/s13225-016-0366-9.

Li HJ, Lin YC, Wang L, Zhou SN, Vrijmeod LLP, Jones EBG. (2001) Metabolites of marine fungus Hypoxylon oceanicum (#326) from the South China. Sea. Acta Scientiarum Naturalium University Sunyatseni 40: 70.

Schatz S (1988) Hypoxylon oceanicum sp.nov. from mangroves. Mycotaxon. 33:413-418.

Schilingham G, Milne L, Williams DR, Carter GT. (1998) Cell wall active antifungal compounds produced by the marine fungus Hypoxylon oceanicum LL-15G256. II. Isolation and structure determination. Journal of Antibiotics 51: 303-316.

Smith GJD, Liew ECY, Hyde KD. (2003) The Xylariales: a monophyletic order containing 7 families. Fungal Diversity 13: 175-208.

Whalley AJS, Jones EBG, Hyde KD, Læssøe T. (2000) Halorosellinia gen. nov. to accommodate Hypoxylon oceanicum, a common mangrove species. Mycological Research 104: 368-374.


Key to species:

      1. Ascomata soft to leathery, 4–0 ± 8 mm in diam., (17.9-)18.7-26(-28) × 7.5-13(-13.5) μm                               H. oceanica

  1. Ascomata carbonaceous, 1.5–2.5 × 0.9–1 mm, in diam., ascospores 24–36 × 10–15 µm                                H. rhizophorae


Image: Halorosellinia oceanica. (a) Surface of pseudostroma with masses of discharged spores above the ostiole. (b) Section of immersed ascoma in the pseudostroma. (c) Ascoma neck with periphyses. (d) Two-layered peridium, outer layer of cells of textura angularis, inner
layer of elongated cells. (e) Ascus with near-mature ascospores. (f) Mature ascus with subapical apparatus. (g) Ascospore dark brown with a longitudinal germ-slit. Scale bar: a=300 μm; b=100 μm; c, d, e, f=30 μm; g=10 μm. Photo reproduced with the permission of the National Taiwan Ocean University.


Type & Location:
Other Specimens:
dead mangrove wood, Cocos fruits.
Andaman Islands, Australia, Belize, Bermuda, Brazil, Brunei, China, Hong Kong, India, Indonesia, Japan, Macau, Malaysia, Mauritius, Nicobar Islands, Philippines, Portugal, Republic of Trinidad and Tobago, Seychelles, Singapore, South Africa, Taiwan, Thailand, USA.
Pertinent Literature:
Mycol. Res. 104: 368 (2000).
This species is extremely common in the upper level of the mangroves. It was originally described as a Hypoxylon species (Schatz 1988), but was transferred to a new genus Halorosellinia because Hypoxylon has: (i) a Nodulisporium-like anamorph, (ii) uni-partite stromata, (iii) solid and homogeneous stromatal tissue, and (iv) height of the stromata less than the length and breadth (Whalley et al. 2000). Sequence analyses based on SSU and LSU rRNA genes suggested a relationship with Xylaria hypoxylon but did not group with Hypoxylon curta, suggesting that the genus Hypoxylon might be polyphyletic (Smith et al. 2003). A second species, Halorosellinia rhizophorae, has been described on submerged root of Rhizophora sp., at Krabi, Thailand (Li et al. 2016). Halorosellinia rhizophorae is clearly different from the type, H. oceanica in lacking ascomatal projections, with larger ascospores (24–36 × 10–15 µm), and forms a sister clade to the type, H. oceanica with 81% bootstrap support. Halorosellinia oceanica produces a wide range of bioactive compounds, including cytochalasins, which is consistent with its taxonomic affinity with Xylariales (Schlingham et al. 1998, Li et al. 2001).
  • Fig 2
    Fig 2


Mushroom Research Foundation 
Chiang Rai 


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