Figs. 6–7. Light micrographs of longitudinal sections through carpels of Platanus racemosa, oriented with chalazal end toward top of page. Scale bars = 100 µm. Figure Abbreviations: CH, chalaza; GPT, female gametophyte; II, inner integument; M, micropyle; N, nucellus; OI, outer integument; OV, ovule; ST, style. 6. Young carpel collected in week 1 prior to megasporocyte stage with pendant, orthotropous ovule showing style, ovule, nucellus, inner integument closed around tip of nucellus, outer integument shorter than inner integument. 7. Later ovule with mature female gametophyte. Outer integument shorter than inner integument, which alone forms the micropyle