Carpenter, William Benjamin, 1813-1885, Dallinger, W. H. (William Henry), 1842-1909 · Philadelphia, Blakiston · leaf 650
refewer in number, andare found upon a dif-ferent part of the pro-thallium. Each of themoriginates in a single cell of its superficial layer, which undergoessubdivision by a horizontal partition. Of the two cells thus producedthe upper gives origin, by successive subdivisions, to the £ neck ofthe… … Fig. 464.—Archegone of Pteris serrulata: A, asseen from above ; a, a, a, cells surrounding thebase of the cavity; b, c, d, successive layers ofcells, the highest enclosing a quadrangular orifice.B, side view, showing A, a, cavity containing thegerm-cell, a\ b, b, walls of the archegone, madeup of…
Microscopy
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