Fig. 4From: Derived woodiness and annual habit evolved in African umbellifers as alternative solutions for coping with droughtWood diversity in selected representatives of Tordylieae Lefebvrea clade (A, C–F) and subtribe Tordyliinae (B). A Capnophyllum macrocarpum (TS): a considerable amount of secondary xylem and inner, parenchymatous metaxylem (dashed line marks approximate boundary between them). B Semenovia lasiocarpa (TS): outer portion of secondary xylem with a mixed, patchy type of the background tissue: distorted pervasive parenchyma is dotted with patches of very thick-walled fibres (lower, left corner). The nature of very narrow cells between vessels is unclear – they may be wide fibres or very narrow vessels. C Scaraboides manningii (TS): section through a root showing exclusively fibrous background tissue. D Cynorhiza typica (TS): secondary xylem with almost exclusively parenchymatous background tissue: rare patches of thin-walled fibres are encircled with dashed line (upper, right corner). E Dasispermum suffruticosum (TS): a considerable amount of secondary xylem: the innermost parts of xylem are parenchymatous, while the rest is fibrous. Vessels are disposed indistinctly. F Dasispermum suffruticosum (RS): transition from vessels with scalariform intervessel pitting (extreme left) to alternate intervessel pitting, axial parenchyma cannot be distinguished from other cells. The bark is stained in violetBack to article page