Figure 3.

Detailed views of the internal structure of female organs. a. A female organ with a broken envelope and its exposed central unit. Note the sheathing envelope (P), central unit (O), and longitudinal ribs with dark coaly residues on them. The central unit is attached to the receptacle by a wide base (arrow). Specimen number 8604a. Bar = 1 mm. b. A view of the envelope apex of the female organ in Fig. 3d with the SEM. Note the elongated cells on the smooth epidermis and slightly elongated cells in the tissue of the envelope (arrows). Specimen number 8604b. Bar = 0.1 mm. c. A view of an envelope fragment with the SEM. Note the smooth surfaces and the border between different parts of the envelope (arrow). Specimen number 8604a. Bar = 50 μm. d. A view of a female organ with the envelope (P) and the central unit (O) with the SEM. The texture and the central unit outline (white arrow) could be traced to the envelope apex (black arrow). On the right, there is another female organ with its apex plunging into the sediment matrix (black rectangle). Specimen number 8604b. Bar = 0.5 mm. e. A detailed view of the rectangular region in Fig. 3d with the SEM. Note the spatial relationship between the envelope (P) and the central unit (O), and the longitudinal ribs (arrow) on the internal walls of the central unit. Specimen number 8604b. Bar = 0.1 mm. f. A detailed view of the apex of the central unit in Fig. 3e (rectangle) with the SEM. Note the septum (arrow) across the central unit (O) apex. The black dot beside the bar is about 20 μm in diameter, the size of an average pollen grain. An entry point for a pollen grain of similar size, if present, would be hard to ignore in this image. Therefore, at least the tip of the upper locule (carpel), which is not eclipsed by the septum vestige or in its shadow, is closed. Specimen number 8604b. Bar = 0.1 mm. g. A cross section of two female organs embedded in the sediment. Note the pale sediment (upper half), dark resin (lower half), and darker stripes of two fused female organs (a and b, outlined by black and white lines, respectively). Specimen number 8604a. Bar = 0.5 mm. h. A detailed view of the female organ in Fig. 3g. Note the septum (arrow) and its smooth connection to the side walls of the central unit. Specimen number 8604a. Bar = 0.1 mm. i. A thin section across the apex of the central unit in Fig. 3f. Note the septum (arrow) separating two locules and its smooth connection to the side walls. Light microscope. Specimen number 8604b. Bar = 0.1 mm. j. A view of the internal surface of an envelope apex with the SEM. Note the converging longitudinal ribs. Specimen number 8604a. Bar = 0.5 mm. k. A detailed view of the rectangular region in Fig. 3j. Note the pollen grain (arrow) adherent to one of the longitudinal ribs on the internal surface of the envelope. Specimen number 8604a. Bar = 50 μm. l. A detailed view of the pollen grain in Fig. 3k. Specimen number 8604a. Bar = 10 μm. m. The rugulate sculpture on the pollen grain in Fig. 3l. Specimen number 8604a. Bar = 2 μm. n. Another pollen grain adherent to the internal surface of the envelope apex. Specimen number 8604a. Bar = 5 μm. o. The rugulate sculpture on the pollen grain in Fig. 3n. Specimen number 8604a. Bar = 2 μm.

Wang et al. BMC Evolutionary Biology 2007 7:14   doi:10.1186/1471-2148-7-14
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