Merciera leptoloba

Cupido, Christopher N., 2003, Systematic studies in the genus Merciera (Campanulaceae): A re-assessment of species boundaries, Adansonia (3) 25 (1), pp. 33-44 : 42

— The Merciera leptoloba (A1) and M. brevi-

folia 1 (A2) groups.

DE CANDOLLE (1830), BUEK (1837), and ADAMSON (1954) considered M. leptoloba and M. brevifolia as distinct species, whereas SONDER (1865) treated M. leptoloba as a variety of M. brevifolia . This study has found no support for SONDER’ s concept of taxon delimitation within the genus. Specimens of M. leptoloba ( Fig. 2, A 1 ) do form a subgroup distinct from specimens of M. brevifolia 1 ( Fig. 2, A2). This separation of the taxa appears weak as they show overlapping ranges in all but one quantitative character, leaf length ( Fig. 4H ). Furthermore, the two taxa cooccur on the Houwhoek Mountains, which makes sub-division on geographical grounds inappropriate. The qualitative characters, corolla lobe shape, and habit ( Table 3) support the recognition of two distinct taxa. Merciera leptoloba and M. brevifolia 1 are distinct from all other groups, except the M. eckloniana (A3) group by the absence of hairs on the back of the corolla lobes, and from M. brevifolia group 2 by the number of calyx lobes, corolla lobes, stamens, and geographical distribution.

Figures

Fig. 1. — Illustrations depicting how floral parts and leaves were measured for the morphometric analysis (not to scale): l = leaf length; b = bract-like leaf length; c = calyx lobe length; o = hypanthium length; ct = corolla tube length; cl = corolla lobe length; s = style length; f = filament length. Illustrations were done from FAA preserved material (Cupido 66, NBG) collected near Pringle Bay.

Fig. 4. — Box and whisker plots depicting the character variation ranges in the six phenetic groups: A, bract length; B, hypanthium length; C, calyx lobe length; D, corolla tube length; E, corolla lobe length; F, style length; G, filament length; H, leaf length; I, leaf width.