Plate CLXXX. — Fig. 1, portion of frond and coccidia ; fig. 2, portion of ditto vertically sliced ; fig. 3, spores from the same ; fig. 4, immature ditto : — all highly magnified.
21. ACANTHOCOCCUS, Hooh.fil. et Harv.
Frons linearis, compressa, distiche ramosa, cartilagineo-carnosa, rosea. Axis solidus, densus, e cellulis minutissimis formatus, tubulis magnis pluriseriatis extus sensim minoribus circunidatus. Periplieria celluli parvis reticulata. Coccidia globosa, in apicibus ramidorum immersa, sporis numerosissimis repleta.
1. Acaxthococcus Antarcticus, nobis, in Loncl. Journ. Bot. vol. iv. p. 261. (Tab. CLXXXI.)
Hab. Cape Horn and the Falkland Islands ; not uncommon, and parasitic.
Frons 4-8 unc. longa, compressa, anguste linearis, basi semilineam vix lineam latitudine, sursum sensim angustata, distiche ramosissima. Rami patentes vel divaricati, nunc flabellatim multifidi, nunc pinnati et bipinnati; secundarii nunc breves subsimplices, nunc longissimi, ramosissimi. Ramuli per totam frondem sparsi, apicem versus crebriores, erecti et erecto-patentes, subulati, 1-3 lineas longi, altemi vel saepius secmidi, simplices vel parum divisi. Coccidia solitaria, globosa, spinis 4-6 magnis subulatis armata, in apicibus ramulorum immersa, sporis numerosissi- mis minutis repleta. Tetrasporas ignotae. Color intense ruber, siccitate obscurior. Substantia firma, cartilagineo- carnosa:— chartfe adhaeret.
We cannot satisfactorily include this plant under any established genus. It belongs, unquestionably, to the Spluerococcece and will stand near Hypnea, from which it differs in the structure of the frond, as well as in the fructification. The densely cellular axis, surrounded by large empty cellules or tubes, is seen in Hypnea musciformis, and also in Gracilaria purpurascens. Outwardly there is a close resemblance between our plant and Heringia rostrata, J. Ag., (Gelidium ? rostratum, Griff. ; Fucus alatm, and angustissimus, Turn.); but, besides the dissimilar fructification, the structure of that plant is uniformly dense, without a trace of large cellules, or tubes. Again, the present plant may be compared with Microcladia, which it approaches in habit ; and to a certain extent, the spinous coccidia may be deemed analogous to the mxolwaatetl favella of that genus ; but, in Microcladia, the axis, far from being the most dense part of the frond, is tubular. Plate CLXXXI. — Fig. 1, ramulus ; fig. 2, apex of ditto with coccidium ; fig. 3, transverse section of ramulus; fig. 4, longitudinal section of coccidium : — all magnified.
22. GRACILARIA, Grev.
1. Gracilaria (?) nigrescens, Hook. fil. et Harv.; radice fibrosa, frondibus purpurascentibus caespitosis e basi irregulariter dickotorna et intricata ramosissimis gracilibus subcylindraceis obscure compressis flexuosis flaccidis carnoso-membranaceis, axillis obtusis sa?pissime latis, ramis decompositis sensim angustatis, ramulis filiformibus v. subulatis acutis, ultimis saepe secundis. G. obtusangula, nobis in Lond. Journ. Bot. vol. iv. p. 260. Sphaerococcus subulatus, /3. nigrescens, Agardh, Sp. Alg. p. 329.
Var. /3. tenuior, ramis strictioribus divaricatis, axillis patentibus.
Hab. Hermite Island, Cape Horn, and the Falkland Islands ; not uncommon. Var. /3. Falkland Islands.
Frons basi repens et fibrosa, filiformis, 4-6 unc. longa, ^lin. lata, subcompressa. Color luride purpureus, ut in G. purpurascente.
In the absence of fructification we refer this doubtfully to the genus Gracilaria, chiefly from its close resemblance to the G. purpurascens in the essential characters of the frond. We have never seen original or any other specimens of the Spluerococcus subulatus, var. nigrescens, and owe the identification of our specimens with that plant to the kindness of our friend Dr. Montagne.
