Chapter 5.pdf - DSpace@UM

grandis, Fig. 34F, and R. vietnamensis, Fig. 34M). Only a few Asian taxa havebroadly elliptic to rounded stomatal outlines, e.g., R. kampucheana, R.sootepensis, R. sundaensis (Fig. 34H) and R. sp. indet 2. Exclusively narrowlyelliptic stomatal outlines can be found in R. uvarioides and exclusively oblongoutlines in R. vidalii (see Table 7 for details).The stomatal length, width and length/width ratios for K. stenopetala, R.macrophylla and R. globosa are not individually distinguished. The stomatal outlinefor K. stenopetala varies from elliptic to narrowly elliptic (Fig. 34N), whereas in R.macrophylla (Fig. 34O) and R. globosa (Fig. 34P), it is exclusively elliptic, and socannot be distinguished from that in the other Rothmannia species.Thus, guard cell length, width, length-width ratio and stomatal outline may beused to a very limited extent in differentiating species within Rothmannia and appearnot useful at all at the generic level.5.4.3 Level of stomata in relation to epidermal cellsThe majority of the investigated Rothmannia species have stomata that are atthe same level as the epidermal cells, including the Asian R. merrillii (Fig. 35F), R.negrosensis (Fig. 35I), and R. sootepensis (Fig. 35G); and the African R. whitfieldii(Fig. 35A), R. annae (Fig. 35B), R. lujae (Fig. 35C), R. fischeri ssp. verdcourtii (Fig.35E) and R. manganjae (Fig. 35H). However, the stomata may also vary from beingat the same level to being sunken (depressed) in relation to the epidermal cells, in R.pseudoternifolia var. pseudoternifolia and R. schoemannii (Fig. 35K) (Asian) and R.longiflora (African). Exclusively sunken stomata appear to occur in e.g., R. eucodon(Fig. 35J), R. ridsdalei (Fig. 35M) (both Asian) and R. fischeri ssp. fischeri (African,Fig. 35L) (see Table 8 for details).154