. Morphology of gymnosperms. Gymnosperms; Plant morphology. CYCADALES 135 closes the pit and that communication between the jacket cells and the central cell is only through fine strands of protoplasm (Plasmodes- men) traversing the pit-closing membrane, and claim that it would be absurd to suggest that protein granules travel from the jacket cells to the central cell. In Dioon edule, according to Chamberlain (46), 139 ^c::^... 1 '.•: 140 Figs. 139-144.—Haustoria of cycads: fig. 139, Cycas revoluta; Xiso; fig. 140, the same X37S; figs. 141-143, Dioon edule; X800; fig. 144, Encepkalartos Lehman
. Morphology of gymnosperms. Gymnosperms; Plant morphology. CYCADALES 135 closes the pit and that communication between the jacket cells and the central cell is only through fine strands of protoplasm (Plasmodes- men) traversing the pit-closing membrane, and claim that it would be absurd to suggest that protein granules travel from the jacket cells to the central cell. In Dioon edule, according to Chamberlain (46), 139 ^c::^... 1 '.•: 140 Figs. 139-144.—Haustoria of cycads: fig. 139, Cycas revoluta; Xiso; fig. 140, the same X37S; figs. 141-143, Dioon edule; X800; fig. 144, Encepkalartos Lehmanii, showing the Plasmodesmen; from a free-hand section which had been treated with sulphuric acid; Xi,ioo. —Figs. 139, 140, after IKENO (27); figs. 141-143, after Chambeklain (46); fig. 144, after Stopes and Fujii (50). substances pass from the jacket cells into the haustoria as readily as from one part of the cell into another. Doubtless a pit-closing membrane exists here, as elsewhere, during the earUer development of the central cell, but as the haustoria grow larger and project into the cells of the jacket, the closing membrane is ruptured. The situation may be better understood from a series of figures by the various investigators (figs. 139-144).. 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 Coulter, John Merle, 1851-1928; Chamberlain, Charles Joseph, b. 1863; Coulter, John Merle, 1851-1928. Morphology of spermatophytes. Part I. Gymnosperms. Chicago, University of Chicago Press
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