Fig. 4

Floral vasculature in the two-staminate flower of A. intermeda ‘chenshengzhen’, related primarily to the carpellary dorsal bundles and parietal bundles supply. All figures are presented in transverse section with the adaxial side upward. Arrow (↑), CDB; arrowhead (▼), PB. a Sublocular region, showing initiating CDBs and PBs. b Locular region, showing invert axile placentation bearing ovules. c, d A little higher above the locular region, showing an extension of the bundles. e, f The upper part of the ovary locules, displaying the anastomosing vascular plexus being formed by the CDBs and PBs bearing branches each other, with some outer large bundles from the ovary wall also joining. , Below the junction of the calyx tube, displaying the calyx tube beginning to differentiate before g the anastomosing vascular plexus fading out. h–j The floral tube, showing the gland emergence and petals starting to separate. k–n, Fully differentiated floral organs, showing petals, labellum, two fertile stamens and three appendages. Bars = 100 μm. g gland; a appendage; s sepal; p petal; st fertile stamen; lab staminodial labellum; sty style