. Dansk botanisk arkiv. Plants; Plants -- Denmark. F. Børgesen: Rhodophyceæ of the Danish W. Indies. 41. Fig. 38 nov. Acrochætium rohustum spec. Base of a plant. (About 450: 1). fluentia, egrediuntur, et sic discum basalem formant, ex cellulis brevi- bus, diametro fere æquilongis, pariete crasso compositum. Fila erecta a basi ramosa, apicem versus sensim pau- lum attenuata, in parte basali 9—10// lata, superne ca. 5 n. Cellulæ cylin- dricæ 9—10// latæ, inferiores 15— 20 fjL longæ, superiores ca. 40 [i longæ, chromatophorum parietale, pyrenoide laterali instructum continentes. Rami sparsi, nonn
. Dansk botanisk arkiv. Plants; Plants -- Denmark. F. Børgesen: Rhodophyceæ of the Danish W. Indies. 41. Fig. 38 nov. Acrochætium rohustum spec. Base of a plant. (About 450: 1). fluentia, egrediuntur, et sic discum basalem formant, ex cellulis brevi- bus, diametro fere æquilongis, pariete crasso compositum. Fila erecta a basi ramosa, apicem versus sensim pau- lum attenuata, in parte basali 9—10// lata, superne ca. 5 n. Cellulæ cylin- dricæ 9—10// latæ, inferiores 15— 20 fjL longæ, superiores ca. 40 [i longæ, chromatophorum parietale, pyrenoide laterali instructum continentes. Rami sparsi, nonnunquam secun- dati, ramulis sparsis, uni-, bi- aut tri- cellularibus, monosporangia gerentibus instructi. Sporangia ovata, ca. 11 /« lata et 12—14// longa. This species was found together with several other species upon old leaves of Sargassum vulgare. The base (Fig. 38) of the plant consists of a pluricellular disc composed of thick- walled cells. From this an unicellu- lar, thickwalled process grows down- wards fixing the plant strongly to the host plant; how far these processes also should serve as haustoria like those described by Rosenvinge for Chantransia cytophaga, I have not been able to decide. The processes reach a length of about 20 fi; the basal disc is about 8—10/< thick. Not having succeeded in finding quite young plants I have not been able to follow the development of the basal disc, but most seemingly the germinating spore produces the process during germination (com- pare Fig, 38) and this grows down- Fig. 39. Acrochætium robustum ^^Yds in the tissue of the host nov. spec. Habit of a plant. (About 140:1). plant; afterwards from its upper end. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Dansk botanisk forening. Kbenhavn : Dansk botanisk forening
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