. Elementary botany. Botany. i68 MOEPHOLOG y. is termed the annulus, which means a Httle ring. While this is not a complete ring, in some other ferns the ring is nearly complete. 350. In the front of the sporangium is another peculiar group. Fig. 205. Rhizome of sensitive fern (Onoclea sensibilis). of cells. Two of the longer ones resemble the lips of some crea- ture, and since the sporangium opens between them they are sometimes termed the lip cells. These lip cells are connected with the upper end of the annulus on one side and with the upper end of the stalk on the other side by thin-walled
. Elementary botany. Botany. i68 MOEPHOLOG y. is termed the annulus, which means a Httle ring. While this is not a complete ring, in some other ferns the ring is nearly complete. 350. In the front of the sporangium is another peculiar group. Fig. 205. Rhizome of sensitive fern (Onoclea sensibilis). of cells. Two of the longer ones resemble the lips of some crea- ture, and since the sporangium opens between them they are sometimes termed the lip cells. These lip cells are connected with the upper end of the annulus on one side and with the upper end of the stalk on the other side by thin-walled cells, which may be termed connective cells, since they hold each lip cell to its part of the opening sporangium. The cells on the side of the sporangium are also thin-walled. If we now examine a sporangium from the back, or dorsal Aspidium edge as we say, it will appear as in the (sori). " left-hand figure. Here we can see how very prominent the annulus is. It projects beyond the surface of the other cells of the sporangium. The spores are contained inside this 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 Atkinson, George Francis, 1854-1918. New York, H. Holt
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