. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. REPRODUCTION, VEGETABLE (VEGETABLE OVUM). 220 transparent. Germination consists in the growing out of this membrane at one end of the spore into a many-celled filament, which escapes through a lacerated opening in the ex- ternal membranes, and gradually assumes the character, and appearance of the parent plant. At the same time a tubular elongation of the same membrane of limited growth is formed in the opposite direction, which is the rudi- ment of a root.* 18. In a species of Palmellese (Palmoglea macrococca) in which
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. REPRODUCTION, VEGETABLE (VEGETABLE OVUM). 220 transparent. Germination consists in the growing out of this membrane at one end of the spore into a many-celled filament, which escapes through a lacerated opening in the ex- ternal membranes, and gradually assumes the character, and appearance of the parent plant. At the same time a tubular elongation of the same membrane of limited growth is formed in the opposite direction, which is the rudi- ment of a root.* 18. In a species of Palmellese (Palmoglea macrococca) in which the whole individual consists of a single ovoid cell containing green granular matter, and usually multiplying itself by successive division, the phenomena of con- jugation present themselves in a somewhat different and very remarkable form. Here two cells, probably the result of a series of divisions, undergo a complete union, affecting not only their contents, but also their mem- branes. They coalesce as completely at their points of contact, as two contiguous drops of water, the result of their union being a cell which differs in no"respect from its predeces- sors, except in the greater thickness of its walls, and in the complete conversion of the chlorophylle of its contents into oily globules. Like the spore of the -Zygnemaceae, it is des- tined to a long period of inactivity, after which, by the successive division of its con- tents, it gives rise to a new series of individuals, similar to those that preceded it. 19. We have still to consider the most remark- able condition under which conjugation takes place among the Alga;. The evolution of the aggregate zoospore of Vaucheria has been already described. In the plant which results from its germination, Karsten has observed that along the course of those filaments which come in contact with the atmosphere are formed organs of a peculiar structure. They originate like the ordinary branches, as nipple- shaped buddings
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