Genus Stilbohypoxylon
Key to Taxa of Stilbohypoxylon
Accepted Taxa
List of Names

Yu-Ming Ju
Michael J. Adams

Stilbohypoxylon Henn. was erected by Paul Hennings (1902); a description and illustration by Alfred Möller (1901) suggested the new genus. Möller's illustrations (1901, Plate VIII, Fig. 107) include two perithecia without asci enclosed in a stroma that bears a synnema. Möller (1901) apparently believed that the stromata were parasitized and considered the synnematal part to be a Sphaerostilbe Tul. & C. Tul. Hennings' diagnosis (1902) of Stilbohypoxylon and his description of the type species, S. moelleri Henn. were based upon material with immature asci. Hennings tentatively put the genus in family Xylariaceae. We have been unable to unequivocally locate Hennings' type, which was given as: St. Cathar. bei Blumenau auf abgestorbenem Holz. No. 708. However, we located at S a specimen labelled: 'Stilbohypoxylon mölleri P. Henn., Brasilia, S. Catharina, leg. A. Möller'. It is of Sydow's herbarium and parts of it look much like Möller's illustration. It is our opinion that this packet was labelled following Hennings' creation of the genus and species and, indeed, Möller might have utilized this very material. Hennings might have examined it or been greatly influenced by illustrations of it. In any case, we designate it as the lectotype of Stilbohypoxylon moelleri. Our case is strengthened by the fact that Höhnel (1910) also examined and discussed a specimen that might well be the specimen in question. He remarked that the specimen is an overmature pyrenomycete lacking ascospores that is associated with a synnematal fungus. Höhnel believed, in essence, that S. moelleri is a member of the Ceratosphaeriaceae that had been colonized by a member of the Hypocreaceae. The material examined by us, and probably by Möller, Hennings, and Höhnel, shows overmature perithecial stromata bearing synnemata, apparently immature perithecial stromata bearing synnemata, and synnemata unassociated with perithecial stromata. Some stromata show yellow scales exactly like numerous other ascospore-bearing specimens that have been examined. There is no evidence of parasitism. We believe that both Möller and Höhnel misinterpreted the yellow scales on the specimen(s) as representing a hypocreaceous fungus, i.e., because this color is fairly common among the Hypocreales. In an examination of a small amount of lectotype material, we saw neither asci nor ascospores. Such might in fact occur, but we refrained from destroying remaining material.

We will probably never be able to establish unequivocally which specimens were examined by Hennings, Möller, and Höhnel, respectively. We are convinced that Hennings based his type species and genus on teleomorphic material -- albeit immature -- and, in fact, gave a good description of his material, except that conidial dimensions are smaller than usually encountered. We believe that, although Hennings interpreted the synnemata correctly, the conidia are of another fungus. Based upon the lectotype we believe that synnemata had matured beyond the conidium-bearing stage (and see later herein). In order to preserve Stilbohypoxylon as a genus, as recognized by various mycologists over the years and to leave no doubt of our concept, we designate the following specimen as the epitype: British West Indies, Grand Etang, on Euterpe sp., coll. R. Thaxter, det. W. G. Farlow, 1913, Reliquiae Farlowianae 633 (S). (The portion at FH is immature.) There is a number of other specimens of Roland Thaxter at FH and, while mostly lacking fully mature teleomorphs, seem entirely typical of the species. It is apparent that what we believe to be the correct concept of Stilbohypoxylon moelleri was established shortly after Hennings published it.

A second species of Stilbohypoxylon, S. rehmii, was erected by Theissen (1908a) on material with mature ascospores. Unfortunately this name has been widely accepted and misinterpreted in the literature. Indeed, Theissen has erroneously been credited with erecting Stilbohypoxylon (Saccardo, 1913)! Most collections of S. moelleri have been misidentified as S. rehmii. Höhnel (1910) examined Theissen's material and concluded that it is a Xylaria that develops in the manner of X. tulasnei Nitschke as described and illustrated (as X. pedunculata 'pusilla') by the Tulasne brothers. He proposed the name X. rehmii (Theiss.) Höhn. for it. We accept this as a Xylaria. It is possibly an earlier name for X. schreuderiana van der Bijl.