Page:The Botany of the Antarctic Voyage.djvu/489

Falklands, etc.] preserved in spirits, as to be scarcely recognizable. I had, at first, on examining dried specimens of Gyttaria Gunnii, fancied that I had made some mistake in the analysis given in my paper in the 19th volume of the Linuean Transactions. The fact is, that when a very thin slice of the dried plant is placed on the field of the microscope, the gelatinous coat of the threads of which it is composed becomes visible; while in the plant preserved in spirits, the jelly seems to form one common mass in which the central tube alone is exhibited, and when the plexus of filaments is drawn out with the point of a lancet, they appear far less curled than they do in situ. Perfect sporidia have not at present been observed in any species.

Plate CLXII. Fit/. I. — 1, Gyttaria Hookeri, Berk., of the natural size, on a living twig of Fagus Antarctica; 2, vertical, and 3, transverse sections of a single plant, of the natural size ; 4, asci and paraphyses; 5, curious state of asci; 6, part of the tissue from the darker part of a specimen preserved in alcohol ; 7, ditto from lighter part artificially extended ; 8, portion of intercellular tissue of Cyttaria Gunnii as seen in a dry specimen ; (the same structure is found in dry specimens of Cyttaria Hookeri, and in Cyttaria Darwinii, after it has been preserved in alcohol and dried for the Herbarium) ; 9, horizontal slice from portion of bark nearest to the wood, in a part of a twig not externally attacked by Cyttaria, to show the mycelium penetrating the cells ; 10, slice of fructifying disc, showing two sorts of tissue of the bark, interrupted by a cavity which is traversed by mycelium ; 11, slice of bark infested with mycelium; 12, slice from the outer surface of the wood; 13, section through a fructifying disc, showing fissures radiating from wood through the spongy portion of the bark, which is greatly increased in volume, and also a cavity traversed by mycelium parallel to the cuticle. The lower portion of the fungus penetrates in this case to the wood ; occasionally, however, it does not penetrate quite so far:— all the above figures, with the exception of the first two, are more or less magnified,

18. ASTERINA, Lev.

1. AsimiyA petticutosa, Berk.; effusa, tenuissirrra, peritheciis punctiformibus depresses atro-fuscis in mycelio fusco a matrice solubili sparsis. (Tab. CLXIV. Fig. I.)

Hab. Chonos Archipelago ; on leaves of an Eugenia ; C. Darwin, Esq.

Amphigena, atro-fusca ; maculae irregulares, varie effusse punctiformesque, e fibrillis radiantibus intertextis ramis patentissimis formatoe, demum e matrice solubiles; interstitiis saepe strato celluloso tenuissimo repletis.

I have not detected fructification ; but the species certainly belongs to the genus Asterina, which is very properly separated from Botlddea by Leveille. The cells of which the perithecimn is composed are elongated, but very irregular, and I find similar cells often filling up the interstices left by the crossing of the radiating threads. Sometimes the mycelium is very obscure and the species then assumes quite a different appearance, the fructifying cells predominating and the patches presenting merely a brown stain studded with darker specks.

Plate CLXIV. Fig. I. — 1, leaves of Eugenia, with Asterina pellicnlosa, Berk., of the natural size ; 2, part of perithecimn seen from the under side ; 3, filaments of mycelium: — highly magnified.

2. Asterina stictica, Berk.; minutissirna, oumino punctiforrnis, mycelio obscuro, peritheciis depressis atro-fuscis margine membranaceo pellucido. (Tab. CLXIV. Fig. IV.)