Fig. 10.

Phloem types according to their fibre arrangement in variant phloem. (A) Transverse section of Callichlamys latifolia, a scarcely fibrous species, with more than ten cells of phloem parenchyma and sieve tube elements between fibre bands (arrows). Note that the phloem fibres (arrows) are thicker than the xylem fibres (arrowheads). (B) Transverse section of Adenocalymma comosum, a semifibrous species, with fewer than ten cells of phloem parenchyma and sieve tube elements between fibre bands (arrows). Note the undulated arrangement of the fibre bands. (C) Transverse section of Xylophragma myrianthum, a fibrous species, with the fibres forming a background tissue where other cell types are embedded. (D) Ancestral character state reconstruction of phloem type evolution. (E) Ancestral character state reconstruction of the percentage of fibres per tranverse area. Scale bars (A, B) = 200 µm; (C) = 120 µm.