. British marine algae : being a popular account of the seaweeds of Great Britain, their collection and preservation. Marine algae. 160 BRITISH MARINE ALG^. pore through which the spores are finally ; Fig. 148 represents a frond of the beautiful and very rare species, Stenogramma interrupta. The fronds of this plant arise from a small discoid root. The stem, which is very shorb, soon expands into a broad, fan-shaped branching membrane ; the segments are flat and cleft, somewhat in the manner of those of Rhodymenia palmetta (Fig. 143), but the colour is much brighter and richer,
. British marine algae : being a popular account of the seaweeds of Great Britain, their collection and preservation. Marine algae. 160 BRITISH MARINE ALG^. pore through which the spores are finally ; Fig. 148 represents a frond of the beautiful and very rare species, Stenogramma interrupta. The fronds of this plant arise from a small discoid root. The stem, which is very shorb, soon expands into a broad, fan-shaped branching membrane ; the segments are flat and cleft, somewhat in the manner of those of Rhodymenia palmetta (Fig. 143), but the colour is much brighter and richer, being a deep rose-red, especially so when the plant is in fruit, and then it is impossible to mistake this brilliant species for anything else. The narrow line or nerve which traverses the segments of the frond, but broken or interrupted here and there by a short space, is thickened about the centre, and is of a brilliant crimson. These swollen portions of the nerve contain the conceptacles, which at maturity are filled with a vast number of very minute spores. Fig. 148 (b) represents a vertical cutting of a conceptacle, the spore mass within raising the upper and depressing the under surface of the central portion of the segment, the inner stratum being composed of large colourless cells, the rich red endochrome being confined to the external layers of small cells on each surface of the frond. This rare plant is annual; it is taken in Cork Harbour; at Minehead, in Somerset; and washed ashore in several situations near Plymouth. Usually, British specimens are from 2in. to 5in. long, but I have dredged some in Plymouth Sound, which were over 8in. long, and several of the divisions which had been injured at the tips had thrown out. Fig. 148. {a) Stenogramma interrupta; (b) Vertical cutting of eonceplucle magnified. a new series of segments from the broken parts, all of which were branched in the same manner as the primary frond. This curious plant is found on the Calif'oruian an
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Keywords: ., bookcentury1800, bookdecade1870, bookpubl, booksubjectmarinealgae
