A recircumscription of Jacobsenia (Aizoaceae): Re-instating Drosanthemopsis, with two new quartz-endemics from Namaqualand, South Africa and sinking Knersia * Author Klak, C. Author Hanáček, P. Author Bruyns, P. V. text South African Journal of Botany 2018 2018-05-31 116 10 67 81 http://dx.doi.org/10.1016/j.sajb.2018.02.402 journal article 10.1016/j.sajb.2018.02.402 1727-9321 14036691 4. Drosanthemopsis vaginata (L.Bolus) Rauschert , Taxon 31(3): 555 (1982). Drosanthemum vaginatum L.Bolus , Notes Mesembryanthemum 2: 138 (1929). Anisocalyx vaginatus (L.Bolus) L.Bolus, J. S. African Bot. 28: 303 (1962), nom. illeg. Jacobsenia vaginata (L.Bolus) Ihlenf., Mitt. Inst. Allg. Bot. Hamburg 27: 124 (1997). Type: South Africa . Little Namaqualand , on the road between Vanrhynsdorp and Bitterfontein , without date, L. Bolus sub NBG1759/29 ( BOL , holo .!) . [Note: The locality of the type collection is thought to be an error, since this species has never been recorded so far to the south ( Ihlenfeldt, 1997 ).] Anisocalyx salarius L.Bolus , Notes Mesembryanthemum 3: 386 (1958), nom. illeg. Drosanthemopsis salaria (L.Bolus) Rauschert , Taxon 31(3): 555 (1982). Type: South Africa . Northern Cape , Riethuis (3017AB), 29 Nov. 1957 , H. Hall sub NBG634/57 ( BOL , holo.!; NBG , iso.!) . Compact shrubs to 8 cm high, main stem in old plants procumbent, young internodes indistinctly papillate becoming smooth with age, difference between long shoots and short shoots indistinct; each stem mostly developing 2 leaf-pairs per season. Leaves basally fused into a sheath, sheath to 10 mm long, grey, usually ascending, upper surface flattened, lower surface towards the apex slightly keeled, 23–35 mm long, 8–11 mm diam.; epidermis with large, ± circular bladder cells with flat top, with many antler like protrusions, especially along the margins. Flowers emerging from the connate portion of the 1st or 2nd leaf-pair of the season, 35–40 mm diam., pedicels 7–10 mm long; sepals mostly 6, rarely up to 8, the two outer ones opposite, the Appendix 1 remaining spirally arranged; petals white; filaments white. Fruit shape of capsule seen from above ± circular to elliptic, 5–9 mm diam., locules 6–13. Seeds brown to light brown, testa minutely papillate, c. 0.7 × 0.5 mm . Ecology and distribution : The species is endemic to a relatively small area around Riethuis, Namaqualand, South Africa ( Fig. 6 ). Here it is found in dense colonies on loamy strongly saline sand overlain with quartz pebbles. Diagnostic characters : Drosanthemopsis vaginata can be distinguished from all other species in the tribe with a similar habit by its remarkable and unique bladder cells ( Fig. 5B ).A very similar epidermis is only found in D. kwaganapensis ( Fig. 5A ), from which it differs by its grey leaves and its low spreading habit ( Table 1 ). Conservation status : Drosanthemopsis vaginata is a rare species, known from only a few localities and is listed by Raimondo (2009) as vulnerable (VU). Additional specimens examined: South Africa . NORTHERN CAPE : 3017 ( Hondeklipbaai ): Riethuis near Komaggas (-AB), Ihlenfeldt & Herre sub SUG13199 ( BOL ); Riethuis (-AB), Wisura 882 ( NBG ); 4 km S of Wallekraal (-BC), Klak 902 ( BOL ); 8 km S of Wallekraal on road to Soutfontein (-BC), Klak 2311 ( BOL ) . Supplementary data to this article can be found online at https://doi. org/10.1016/j.sajb.2018.02.402.