Figs. 33–41. Mourera fluviatilis: development of spathellas and flowers. 33. Flower primordium (F), surrounded by two-lobed spathella (Sp) and distal sheath (dS) of bract (Bx + 1, with warts). Next older bract (Bx) removed. Scale bar = 100 µm. 34. Another flower primordium (F) covered by collar-like spathella (Sp). Arrow points to warts of adjacent bract. Scale bar = 100 µm. 35–38. Four consecutive stages of floral development, after removal of spathella (Sp). 1–3, centrifugal inception of stamen primordia (1–2) and tepal primordia (3) on common girdling primordium (A). G, two-lipped gynoecium primordium. Scale bars = 100 µm. 39. Mid-developmental stage of flower. Gynoecium (G) with primordial styles. 1, inner stamen whorl (incomplete) with extrorse anthers. 2, outer stamen whorl (complete) with introrse anthers. 3, complete whorl of tepals alternating with outer stamen whorl. Scale bar = 100 µm. 40. Older developmental stage of flower, after partial removal of spathella (Sp) and bract (B). Outer stamen whorl with sagittate introrse anthers (2), alternating with tepals (3). Arrow points to warts on bract. Scale bar = 1 mm. 41. Upper third of postanthesis placenta covered with many young seeds, after removal of ovary wall and styles. Arrows point to septum dividing the ovary into two locules. Scale bar = 500 µm.
