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. 2013 Aug 13;8(8):e72688. doi: 10.1371/journal.pone.0072688

Figure 2. Apical gynostemium structures of Bulbophyllum bicoloratum viewed under the stereomicroscope (A, B) and scanning electron microscope (C–E).

Figure 2

(A) Isolated column of an outcrossing individual with erect rostellum at anthesis (without pollinia); (B) isolated column of a selfing individual with ‘displaced’ (suberect) rostellum at pre-anthesis (note, at anthesis, swollen pollina will obstruct the view on the rostellum; compare E); (C) column of a selfing individual with pollinia still in the anther at pre-anthesis; (D) close-up of the ‘displaced’ (suberect) rostellum (same as C) with the viscidium at its apex and cuticular folds on the upper (adaxial) side (except for the lateral sides); (E) column of a selfing individual after pollinia have been released from the anther onto the ‘displaced’ (suberect) rostellum. The swollen outer pollinia contact the (semi-) lateral rims of the stigmatic cavity (arrow). The dashed lines of planes 1–3 indicate approximate positions of longitudinal micro-CT sections shown in Figure 4A–C, respectively. The arrow below indicates the directionality of the complete scan (see Video S3), with numbers identifying scan-frames roughly corresponding to planes 1–3. Abbreviations: a, anther; c, column (gynostemium); dr, ‘displaced’ (suberect) rostellum (with cuticular folding); lr, lateral sides of ‘displaced’ (suberect) rostellum (devoid of cuticular folding); p, pollinia; ip, inner pollinium; op, outer pollinium; r, rostellum; s, stigmatic cavity; sr, rim of stigmatic cavity; st, stelidium; v, viscidium. Scale bars: (A, B) = 0.5 mm; (C, E) = 0.2 mm; (D) = 0.1 mm.