Pavetta trichardtensis var. jabulanii N. Hahn, 2022

Hahn, Norbert, 2022, Pavetta trichardtensis (Rubiaceae) and its varieties, Phytotaxa 533 (4), pp. 216-222 : 219-221

Pavetta trichardtensis var. jabulanii N. Hahn , var. nov. ( Fig. 1–3 )

Type:— SOUTH AFRICA. Limpopo: Hanglip , 6 December 2019, N . Hahn 3129 (holotype ZPB!; isotypes PRE!, PRU!)

Diagnosis:— Pavetta trichardtensis var. jabulanii is easily distinguished from the typical variety by its glabrous, shiny dark green leaves with sunken bacterial nodules above and glabrous calyx opposed to pubescent thinly textured leaves with bacterial nodules not prominent above and pubescent calyx ( Fig. 2 ). In addition, var. jabulanii has on average smaller leaves (1.8–)3.5–6.8(–8.7) × (0.9–)1.7–2.9(–3.5) cm and petioles (0.3–)0.3–0.9(–1.4) cm long opposed to (2.6–)4.4–8.3(–8.9) × (1.4–)1.9–3.8(–5.3) cm and petioles (0.4–)0.6–1.2(–1.5) cm long for var. trichardtensis .

Distribution:—Soutpansberg, Blouberg and possibly Houtbosch [Woodbush] ( Fig. 1 ). The specimen, Houtbosch, Rehmann 6016 (K) cited under the description of P. zoutpansbergensis ( Bremekamp 1934) was not examined. Rehmann 6016 is presently the only specimen of P. trichardtensis var. jabulanii recorded south of the Soutpansberg and Blouberg ( Fig. 1 ).

Conservation status:— Least Concern (LC). Pavetta trichardtensis var. jabulanii encompasses an EOO of approximately 8891 km 2 and an AOO at a 2 km cell width of 88 km 2 or AOO at a 5 km cell width of 525 km 2. This variant was possibly collected south of the Soutpansberg in 1875. Even though var. jabulanii EOO and AOO would fall under the Vulnerable category, the Soutpansberg and Blouberg communities seem to be quite stable and therefore do not fulfil any of the additional criteria for such listing. This variety does not qualify for any of the threatened categories and is therefore assigned a conservation status of Least Concern.

Eponymy:—I have the honour of dedicating the specific epithet to Jabulani Linden, long standing friend and naturalist par excellence who has assisted and collaborated with me over many years to the conservation and natural history of the Soutpansberg. Jabulani is a fitting epitaph which has its origin from the isiZulu word meaning “rejoice” as this is a joyous occasion, finally having resolved the identity of the glabrous variant of Pavetta trichardtensis .

Specimens examined:— SOUTH AFRICA. Limpopo: Budworth (2229 DD), 8 December 1956, E . Prosser 2013 ( PRE); Highfield (2229 DD), 5 December 1993, N . Hahn 644 ( ZPB); Hanglip (2229 DD), 6 December 2019, N . Hahn 3129 ( PRE, PRU, ZPB); Tsamavhudzi (2230 CB), 12 December 1993, N . Hahn 677 ( ZPB); Lamiluzi (2230 CC), 26 January 1992, N. N . Hahn 301 ( ZPB); Fundudzi (2230 CD), 17 April 1975, A. E . Van Wyk 2709 ( PRE); Thathe Vondo (2230 CD), 16 December 1976, G . Hemm 30 ( PRE), 8 December 1977, G . Hemm 405 ( PRE), 26 November 2002, N . Hahn 1939 ( ZPB), 9 December 2008, N . Hahn 2360 ( ZPB), 26 November 2002, B . Bremer, P . Kornhall, N . Hahn & S.P. Bester 4350 ( PRE); between Dzamba and Khaku (2230 CD), 22 May 1982, A. E . Van Wyk 5661 ( PRE), 1 February 1982, A. E . Van Wyk, R. M. T . Dahlgren & P .D.F. Kok 5442 ( PRE); Entabeni (2230 CD) 2 May 1992, N . Hahn 347 ( ZPB); Thengwe (2230 CD), 8 December 2004 , D.M. McMurtry 12202 ( PRE); Beauley (2329 AA), 9 December 1992, N . Hahn 443 ( ZPB), 7 March 2009, N . Hahn 2440 ( ZPB); Blaauwberg (2329 AA), 27 December 1923, J. C . Smuts & I. B . Pole Evans 902 ( PRE); Dantzig (2329 AA), 5 December 1990, R. H . Archer 500 ( PRE); Llewellyn (2329 AB), 8 January 1985, S . Venter 10468 ( PRE); Bergplaats (2329 AB), 9 January 2019, N . Hahn & J. Linden 3123 ( PRE, PRU, ZPB); Hanglip (2329 BB), 26 January 1931, C. E. B . Bremekamp & H. G. W. J . Schweickerdt 441 ( PRE), December 1983, A. E . Van Wyk 6651 ( PRE); Entabeni (2330 AA), 2 December 1956, R . Brent 99 ( PRE); Goedgevonden (2330 AA), 11 February 1995, N . Hahn 1085 ( ZPB); Tshakoma [Tshakuma] (2330 AB), 1 November 1931, A. A . Obermeyer 1122 ( M, PRE) .

Figures

FIGURE 1.—Distribution of both varieties of Pavetta trichardtensis overlain across the geomorphic provinces of South Africa (Partridge et al. 2010) also including the Blouberg, Makgabeng and Soutpansberg (Hahn 2011).

FIGURE 2.—Pavetta trichardtensis var. jabulanii. A. Closeup of inflorescence showing characteristic glabrous ensiform calyx. B. Shiny green upper leave surface showing sunken bacterial nodules. C. Flowering branchlet. D. Underside of leaves showing hairy domatia situated in the axial of the main- and secondary veins.

FIGURE 3.—Comparative vegetative and flowering charts between P. trichardtensis var. jabulanii and P. trichardtensis var. trichardtensis.