. An introduction to the structure and reproduction of plants. Plant anatomy; Plants. SEXUAL REPRODUCTION (FUCUS) 225 septa. The antheridia are oval cells, which likewise possess relatively thick walls and occupy the ends of most of the short lower segments of richly branched hairs (Fig. 120, I).i In each are formed numerous minute bicihate spermatozoids (Fig. 120, L), containing a well-marked nucleus, but only traces of a chloroplast. The mature antheridia have a yellowish colour, which they impart to the entire conceptacle, and by this means, in the dicecious species, the male plants can be
. An introduction to the structure and reproduction of plants. Plant anatomy; Plants. SEXUAL REPRODUCTION (FUCUS) 225 septa. The antheridia are oval cells, which likewise possess relatively thick walls and occupy the ends of most of the short lower segments of richly branched hairs (Fig. 120, I).i In each are formed numerous minute bicihate spermatozoids (Fig. 120, L), containing a well-marked nucleus, but only traces of a chloroplast. The mature antheridia have a yellowish colour, which they impart to the entire conceptacle, and by this means, in the dicecious species, the male plants can be Fig. 121.—The Bladder Wrack [Fiiciis vesictilosus). A, Transverse section through a fertile conceptacle containing oogonia, in different stages of development. B, Small part of a transverse section through the thallus, more highly magnified, a., assimilating laj'er ; m., medulla ; s., storage cells ; w., wall of conceptacle. WTien the cells are ripe, the outermost layer of the antheridium or oogonium, as the case may be, breaks open and sets free the contents which remain enclosed in the inner part of the wall. The gradual extrusion of the packets of ova, or spermatozoids, from the opening of the conceptacle often occurs between the tides, and is probably largely brought about by expansion of the mucilage, secreted by the hairs, combined with ' These antheridial hairs are best examined by teasing out the contents of a male conceptacle in a drop of water. 15. 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 Fritsch, Felix Eugene, 1879-; Salisbury, E. J. (Edward James), Sir, b. 1886. London, G. Bell and sons ltd.
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectpl, booksubjectplants
