Fig. 5
From: Heterochrony and repurposing in the evolution of gymnosperm seed dispersal units
Morphology and anatomy of seed and pollen cone bracts and leaves of E. multiflora. A Seed cone with three seeds (s) and papery-winged bracts (arrow). B–D Cross section of the papery-winged seed cone bract (young green stage). C Polarized light microscopy of section in B. D Detail of vascular bundles and mucilage chlorenchyma cells (arrows). E, F General appearance of papery-winged seed cone bract in cross section, stained with PAS and toluidine blue O. Arrows indicate the two vascular bundles, and arrowheads the lateral papyraceous area. G Pollen cone after pollination, with open microsporangia (arrowheads) and papery-winged bracts (arrows). H, I Cross section of pollen cone bract. I Polarized light microscopy of section in H. J–O Leaf development. J Cross section of a terminal bud, with leaves from node 1 (n1) and leaf primordia (p). K Polarized light microscopy of section in J. L–O Detail from the youngest leaf primordia to a node 1 leaf. P, Q Histochemistry of a leaf primordium (same stage as L) revealing mucilage chlorenchyma cells (arrows), P Alcian Blue, Q PAS. R Mucilage cells turning into tanniniferous cells in a node 1 leaf. S, T Cross section of a seed cone bract with mucilage cells (arrows). S PAS. T Alcian Blue. Adaxial epidermis (ead), abaxial epidermis (eab), fibers (f). Scale bars: 1 mm (A, G); 500 µm (J, K); 400 µm (E, F, O); 300 µm (N); 200 µm (B, C, H, I, M); 100 µm (D, L, P, Q, S); 50 µm (R, T)