Fig. 6. Development of sporophytes. Sporophytes of the wild type (A-D) and the PpLFY double disruptants (E-K) were observed by light microscopy of the 5 µm sections (A,B,D,H-K) or by stereoscopic microscopy (C,E-G). (A,B) A developing sporophyte (bracket) within an archegonium venter. (C,D) A mature sporophyte. A columella (co; tissue within the double-headed arrow) and a capsule wall (cw; the layer of cells between the two arrows) were differentiated. (E-G) An aberrant sporophyte. The arrow in E indicates an undifferentiated archegonium. (F) A sporophyte with double sporangia. (G) A withered and dehisced sporophyte. (H) A young sporophyte (bracket) that is arrested in development within an archegonium. (I-K) Sporophytes with an abnormal sporangium, seta and foot in abnormal morphology. Double-headed arrows indicate aberrant columella (co) and capsule walls (cw) differentiated (J,K). Single headed arrows indicate differentiated spores. Scale bars: 100 µm.