. Botany for high schools and colleges. Botany. 276 BOTANY. the pericarp, in addition to tlie parts found in the latter genus. 369.—In the genus Dudresnaya there is a curious and complicated sexual process. After the fertilization of the trichogyne, a long " connecting tube" {d, Fig. 186) grows out from beneath the trichophore, and comes in contact with the fertile branches (/, /, Fig. 186), to the ter- minal cells of which it becomes closely applied. These fertile branches, which grow as lateral branches on the same plant as the trichogyne, are the true female or- gans, and fertiliz
. Botany for high schools and colleges. Botany. 276 BOTANY. the pericarp, in addition to tlie parts found in the latter genus. 369.—In the genus Dudresnaya there is a curious and complicated sexual process. After the fertilization of the trichogyne, a long " connecting tube" {d, Fig. 186) grows out from beneath the trichophore, and comes in contact with the fertile branches (/, /, Fig. 186), to the ter- minal cells of which it becomes closely applied. These fertile branches, which grow as lateral branches on the same plant as the trichogyne, are the true female or- gans, and fertilization is consummated only when the connecting tube comes in contact and coalesces with them. The result of this curious process is the production of a spo- rocarp on each fertile filament. (a) This class is a large and interesting one, but un- fortunately it cannot be studied readily except near the seaside, and even then, from the fact tliat the species mostly inhabit the deeper waters, it presents many difficulties. The plants are mostly red or violet in color, although this is not due to the absence of chlorophyll. The red color is due to the presence of a pigment (pliycoerythrine), which is soluble in cold fresh water ; its solution is carmine-red in transmitted light and reddish yel- low in reflected light. Upon extraction of the phycoerythrine the plants are found to be green from the presence of the chlorophyll which had been masked by the brigliter pigment. (6) There are many orders in this class, the following of which are represented in the United States.* * The sequence of the orders is that given by Dr. Farlow in his " List of the Marine Algse of the United States," 1876, published in the. Fig. 186.—Ihtdreanaya pvrpvHfera. tr, tricho- gyne, with gpermatozojde altnched; cl, connecting- tube which grows out from below the basse of the trichogyne, and comes in contact with the fertile branches, /, f; ct', young connecting-tube.—After Thurct and
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