Figure 5

Comparative flower ontogeny of dioecious Lepidium sisymbrioides and two hermaphroditic relatives by scanning electron microscopy. (A, E, I, M) L. naufragorum. (B, F, J, N) L. tenuicaule. (C, G, K, O) Staminate L. sisymbrioides. (D, H, L, P) Carpellate L. sisymbrioides. In some panels, organs have been removed. Floral developmental stages noted below follow Arabidopsis thaliana stages [20, 61, 62]. (A-D) Initiating floral primordia within an inflorescence with sepals beginning to enclose the floral meristem, numbered 1 to 5 according to floral developmental stage. (E-H) Petal, stamen, and gynoecium primordia develop, stages 6 to 8. (I-L) Locules of the androecium have differentiated; gynoecium fuses and begins lateral expansion of carpels and stigmatic papillae begin to develop in I-J and L, stages 10 to 11, but arrest in K. (M-P) Stigma differentiates from subtending style in M-N and P, stage 12, but arrests in O; stamen filaments expand in M-O, but remain short in P; petals expand in M, but remain aborted in N-P. Scale bar =100 μm in A-N, P; 200 μm in O. FM, floral meristem; G, gynoecium; IM, inflorescence meristem; N, nectary; P, petal; Se, sepal; Sg, stigmatic papillae; St, stamen.