. The anatomy of woody plants. Botany -- Anatomy. 44 THE ANATOMY OF WOODY PLANTS tangential walls, a feature commonly found in the case of fibrous elements in the terminal region of the annual ring in the conifers and allied groups. The septate tracheid is the most striking feature of the diagram. In this element numerous transverse walls interrupt the continuity of the central lumen. Certain of these transverse partitions are characterized by the pres- ence of bordered pits, while others offer to the eye pits of the simple type. In a third condition bordered and simple pits confront one anoth
. The anatomy of woody plants. Botany -- Anatomy. 44 THE ANATOMY OF WOODY PLANTS tangential walls, a feature commonly found in the case of fibrous elements in the terminal region of the annual ring in the conifers and allied groups. The septate tracheid is the most striking feature of the diagram. In this element numerous transverse walls interrupt the continuity of the central lumen. Certain of these transverse partitions are characterized by the pres- ence of bordered pits, while others offer to the eye pits of the simple type. In a third condition bordered and simple pits confront one another in the same wall. Those cells which communicate with the surrounding elements by means of simple pits are typically occupied by protoplas- mic contents, while the elements possess- ing pores of the bordered category are invariably without living substance. It will be clear to the reader that, if the diagrammatic representation presented in Fig. 34 is correct, the parenchymatous elements of the wood come from the sub- division of the primordial elements which would in other cases and under different circumstances give rise to ordinary tra- cheids. At an early stage these elements became transversely septate, and in the segments so set off the protoplasm some- times persists (when a typical parenchy- matous element of the wood is the result); at other times it disappears with the complete differentiation of the walls surrounding it (in the case of so-called short tracheids). An interesting fact in this connection is the occurrence of paren- chymatous storage elements in the same region of the wood where the tangential pits take their origin. It has been made. KET FIG. 34.—Diagrammatic representation of the origin of wood parenchyma in the 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 Jeffrey, Ed
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