. A handbook of cryptogamic botany. Cryptogams. Fig. 9.—Salvinia naians. Longitudinal section through megaspore and prothallium. a, wall of sporange; ^, epispore, formed of hardened mucilage; c, coat of" spore ; d, diaphragm separating prothallium from spore-cavity ; ^r, prothallium; m, neck of archegone ; /, //, first two leaves of embryo ; j, scutiform leaf or cotyledon. (After Pringsheim, x 70.). Fig. io.—Archegone of Salvinia natans in three stages, a, b, c, divisions in the neck-cells ; rf, neck-canal-cell: f, oosphere ; A, neck-cells. (After Pringsheim, x ^50.) is fertilised, no oth
. A handbook of cryptogamic botany. Cryptogams. Fig. 9.—Salvinia naians. Longitudinal section through megaspore and prothallium. a, wall of sporange; ^, epispore, formed of hardened mucilage; c, coat of" spore ; d, diaphragm separating prothallium from spore-cavity ; ^r, prothallium; m, neck of archegone ; /, //, first two leaves of embryo ; j, scutiform leaf or cotyledon. (After Pringsheim, x 70.). Fig. io.—Archegone of Salvinia natans in three stages, a, b, c, divisions in the neck-cells ; rf, neck-canal-cell: f, oosphere ; A, neck-cells. (After Pringsheim, x ^50.) is fertilised, no others are formed; if not, it is followed by a few others. The archegone of Salvinia is a nearly globular cavity, its venter being completely buried in the tissue of the prothallium. The central cell is at first somewhat elliptical, its axis lying obliquely to the surface of the prothallium. Its apex is at first covered by four cells belonging to the epiderm, arranged in the form of a cross. Each of these four neck-cells divides by transverse septa into a row of three cells, the four rows thus forming a short neck. The large central cell now elongates upwards •and forces its way between the lowermost four cells of the neck, and its. 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 Bennett, Alfred W. (Alfred William), 1833-1902; Murray, George Robert Milne, 1858-. London, New York, Longmans, Green, and Co.
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