Drosanthemopsis vaginata (L.Bolus) Rauschert

Klak, C., Hanáček, P. & Bruyns, P. V., 2018, A recircumscription of Jacobsenia (Aizoaceae): Re-instating Drosanthemopsis, with two new quartz-endemics from Namaqualand, South Africa and sinking Knersia *, South African Journal of Botany 116 (10), pp. 67-81 : 79

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.

Figures

Fig. 6. Distribution of Drosanthemopsis and Knersia, with phytochoria indicated (Knersvlakte,Riethuis-Wallekraal, Southern Richtersveld).

Fig. 5. Scanning electron micrographs of the leaf epidermis found in the Drosanthemopsis clade.A. D.kwaganapensis, Klak 2379 (BOL),showing the conspicuous antler-like protrusions; B. D.vaginata, Klak 2311 (BOL),with antler-like protrusions similar to those found in D.kwaganapensis; C. D.bella, Klak 2309 (BOL),with fewer and smaller antler-like protrusions than found in A&B.D. D. diversifolia, Klak 883 (=Knersia diversifolia) (BOL).