Fig. 1.

Fruits and transverse sections of peduncles of M. sylvestris (construction type 1, A–E) and M. fusca (type 2, F–K) at different stages of fruit development. (B, C) Fibre caps in matured peduncles of type 1 are arranged in an open, flower-shaped ring – enclosed by a massive ring of thick-walled sclereids. (G, H) Mature peduncles of type 2 possess a closed ring of fibres – enclosed by a small layer of thin-walled sclereids. (D, J) Fibres with moderately thickened, lignified cell walls (primary cell-wall layers in green), and beginning formation of sclereids 18 d after full bloom. (E, K) In pedicels only scattered vessels are lignified. Staining: (B, C, G, H) Carmino Verte de Mirande; lignified tissues are stained green-blue, cellulose cell walls pink. (B, C, G, H) Wacker; lignified tissues are stained red–orange, cellulose cell walls green–blue. Scale bars: (A, F) = 10 mm; (B, G) = 200 µm; (C–E, H–K) = 50 µm. Abbreviations: c, collenchyma; cp, cortical parenchyma; cr, crystal clusters; e, epidermis; fb, fibres; p, phloem; pp, pith parenchyma; scl, sclereids; x, xylem.