. Studies in fossil botany . Paleobotany. STIGMARIA 255 however, we find an addition of radially arranged secondary wood (see Fig. 104, 3?), and where this is the case the secondary formation is always limited to the side remote from the protoxylem, thus affording yet another indication of monarch structure. The formation of secondary wood, though rare in the free rootlets, is. JOX. DC Fig. 104.—Stigmaria ficoides. Transverse section o central part of rootlet, to show secondary thickening of wood, jr, primary xylem ; px, protoxylem ; -r2, secondary xylem, limited to one side of bundle ; , i
. Studies in fossil botany . Paleobotany. STIGMARIA 255 however, we find an addition of radially arranged secondary wood (see Fig. 104, 3?), and where this is the case the secondary formation is always limited to the side remote from the protoxylem, thus affording yet another indication of monarch structure. The formation of secondary wood, though rare in the free rootlets, is. JOX. DC Fig. 104.—Stigmaria ficoides. Transverse section o central part of rootlet, to show secondary thickening of wood, jr, primary xylem ; px, protoxylem ; -r2, secondary xylem, limited to one side of bundle ; , inner cortex. X nearly igo. From a photograph by Mr. L. A. Boodle. Will. Coll. 651. commonly found in the rootlet-trace, where it passes through the cortex of the main axis. The branching of the rootlets was by dichotomy. A transverse section of a rootlet at the point of bifurcation is shown in Fig. 105. The plane of division passes through the protoxylem, and coincides with the plane of symmetry of the bundle. The dichotomous branching is an obvious point of agreement with the roots of modern Lycopods. Something may now be said of other forms of. 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 Scott, Dukinfield Henry, 1854-1934. London, A. and C. Black
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