Page:The Botany of the Antarctic Voyage.djvu/200

174 Hab. Lord Auckland's group ; on the leaves of Panax simplex, Forst. Macula omnino superficiales, orbiculares, epiphylte, 2 lin. latse, opacse, olivaceo-nigrce, Lichenem parvum Fucumve referentes, lobatfe, lobis apice dilatatis e filamentis approximatis constantibus.

This pretty species, which was unfortunately not found in fruit, resembles somewhat Rhytisma quercinum, Rudolph, for which I am indebted to Dr. Montague. That species, however, originates beneath the cuticle, while this is, I believe, entirely superficial. The ramification is different, the tips of the branches being dilated in a flabellate form. The stroma, also, consists of approximated threads, not of an irregular cellular membrane. This structure is almost identical with that of Myrionema punctiforme, Harv., except that the filaments are there much branched, which I do not find to be the case here.

This species is accompanied with another in a very imperfect state, and which may be a species of Dothidea.

Plate LXVIII. Fig. VII. — 1, leaf of Panax, with fungus, of the natural size ; 2, portion of the same, magnified; 3, filaments, very highly magnified.

8. HYSTERIUM, Tod.

1. Hysterium breve, Berk.; peritheciis brevibus ellipticis nigris prominulis, rima angustissima, ascis linearibus elongatis. (Tab. LXVIII. Fig. VIII.)

Hab. Campbell's Island ; on the dead leaves of Uncinia Hookeri, Boott.

Perithecia minuta, nigra, nitida, prominula, breviter elliptica, raro utrinque apiculata, rima angustissima. Asci elongati, liueares, paraphysibus filiformibus rectiuscidis immixti, sporidiis fibformibus.

This species is manifestly different from the small form of H. culmigenum, and the nature of the asci and paraphyses are further distinct, being in the latter plant shorter and of a different form, with the apices of the paraphyses curved or curled. The apiculate extremities may not prove to be a constant character, though the probability is that it will, at least in full grown specimens.

Plate LXVIII. Fig. VIII. — 1, leaf and fungus of the natural size; 2, portion of the same; 3, peritheeium shewing the contained asci ; 4, ascus ; all more or less magnified.

9. AYLOGRAPHUM, Mberf.

1. Aylogeaphuh Bromi, Berk.; peritheciis simplicibus filis arachnoideis comitatis, sporidiis oblongis uniseptatis medio constrictis. (Tab. LXVIII. Fig. IX.)

Hab. Lord Auckland's group; on the leaves of Bromus antarcticus.

Mycelium arachnoideum, fuscum, quandoque abundantius et sterile, in maculis autem fertilibus parcum. Perithecia minima, oblonga, brevia, recta v. curvata, simplicia, atra, nitida. Asci brevissimi, obovati, tenerrimi. Sports octonae, oblongo-ellipticse, medio constricts, uniseptatse.

The species of this genus, which has principally been investigated by Madame Libert, resemble extremely minute Opegrapha. The present individual approaches the A. junceum, but differs from it and from all others by the septate sporidia. The peritheeium easily breaks up into its elemental cells, and such I find to be also the case with some of Madame Libert's species ; while, in others, the cellular structure is more permanent and forms a beautiful microscopic object.

Plate LXVIII. Fig. IX. — 1, a portion of leaf and fungus, of the natural size ; 2, peritheeium, magnified, showing the contained asci; 3, ascus ; and 4, sporidia: — highly magnified.