. Botany for high schools. Botany. THE BROWN ALGM duction takes place by zoospores formed in single-celled spore cases (sporangia) in large groups upon the blades. Sexual reproduction is not known. 382. The rockweeds, Fucus.—The species of Fiicus are very numerous and widely distributed in the temperate and arctic seas. They can be seen often in vast quantities attached to the rocks at low tide when they are often uncovered. The short stalk is attached to the rock by a disk-like holdfast. The blade is branched in a forked manner, and the middle line is thickened in the form of a midrib. Growth
. Botany for high schools. Botany. THE BROWN ALGM duction takes place by zoospores formed in single-celled spore cases (sporangia) in large groups upon the blades. Sexual reproduction is not known. 382. The rockweeds, Fucus.—The species of Fiicus are very numerous and widely distributed in the temperate and arctic seas. They can be seen often in vast quantities attached to the rocks at low tide when they are often uncovered. The short stalk is attached to the rock by a disk-like holdfast. The blade is branched in a forked manner, and the middle line is thickened in the form of a midrib. Growth takes place in a small depression at the apex of each leaf. Some species are provided with large bladder- like vesicles in the leaves (Fiicus vesiciilosus). The sexual organs are developed in small cavities called conceptacles. In some species the male and female organs are on different plants (dioe- cious), in others they are in different conceptacles of the same plant (monoecious), while in some both are formed in the same conceptacle (hermaphrodite). These conceptacles are grouped in definite patches, their conical mouths, slightly elevated, giving a punctate appearance, which is easily observed. The concep- tacles are oval or flask-shaped, and numerous slender filaments arise from the bottom and sides and project through the opening. The egg cases are large rounded bodies attached by a stalk to the. Fig. 197. Section of conceptacle of Fucus, showing oogonia and tufts of antheridia. Fig. 198. Oogonium of Fucus with ripe 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 Atkinson, George Francis, 1854-1918. New York, H. Holt and Company
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectbotany, bookyear1910
