5.2. Drosanthemopsis

Rauschert, Taxon 31(3): 555 (1982).

Type: Drosanthemopsis vaginata (L.Bolus) Rauschert.

Anisocalyx L.Bolus, Notes Mesembryanthemum 3: 385 (1958) non Hance ex Walpers, Bot. Syst. (Walpers) 3(2): 195 (1852), nom. illegit.

Type: Anisocalyx salarius L.Bolus.

Knersia H.E.K.Hartmann & Liede, Bradleya 31: 126 (2013), syn. nov.

Type: Knersia diversifolia H.E.K.Hartmann & Liede.

Succulent perennial caespitose shrublet, main stems erect to 150 (− 200) mm high or procumbent to 80 mm high, stems to 10 mm diam.; difference between long and short shoots distinct or indistinct. Leaves succulent, opposite, basally free or fused into a sheath, dirty green to reddish, rarely grey, ascending, trigonous to club-shaped, upper surface flattened, lower surface towards the apex distinctly keeled or keels indistinct to apically rounded, to 8–35 mm long and 4–11 mm diam., at least the last leaf-pair of the season persisting on the stem until the next season; leaf-pairs of a season isophyllous, basally free or connate for c. 1 / 5 of their length; epidermis with large bladder cells with thickened outer walls, cells 0.075 mm to 0.3 mm diam., ± circular to polygonal, bladder cells with flat top either covered with tiny protrusions on their surface or with many antler-like protrusions, especially along the margin. Flowers terminal, solitary, emerging from the connate portion of the 1st leaf-pair of the season, 32–40 mm diam., pedicels 6–23 mm long, sepals 6 (to 8), succulent, the two outer calyx lobes opposite and bigger than the inner four lobes, petaloid staminodes in 4 or 5 rows, pink or white or pink with white centre, inner petals shorter, filamentous staminodes very few or absent, filaments white or yellow, papillate at bases; nectary a crenulate ring; flowering July to September. Fruit a hygrochastic capsule, borderline between expanding keels and expanding sheets distinct; covering membranes covering more than ¾ of the locule, without additional closing devices below the covering membranes, closing bodies absent, present or infrequently formed, numerous sterile funicles in the upper part of the placenta, valve wings broad; locules 6–9(−16), 5–17 mm diam. Seeds with translucent testa or testa ochre to brown, testa minutely papillate, c. 0.7 × 0.5 mm.

Ecology and distribution: Four species endemic to South Africa, from south of Port Nolloth, Northern Cape, to the Clanwilliam district, Western Cape (Fig. 6). In shallow rocky soils, in loamy often strongly saline ground, with a cover of quartz-gravel, mean annual precipitation of estimated 129 mm rainfall p.a. mainly from August to September (Mucina et al., 2006).

Diagnostic characters: Drosanthemopsis shares many characteristics with Jacobsenia (see 5.1), which prompted Ihlenfeldt (1997) to include D. vaginata in Jacobsenia. Differences between the two genera are given in Table 1. Certain epidermal characters in Drosanthemopsis are unique within the Aizoaceae (Fig. 5).

5.2.1. Key to Drosanthemopsis:

1. Leaves bright or dirty green, often suffused with red, 8–18 mm long…...………………………..…..………….………………………………...2

1.’ Leaves grey, 23–35 (−40) mm long…………………… 4. D. vaginata

2. Erect to spreading, loosely branched shrubs; leaves 3–4 mm diam..…. ……………………..………………………………1. D. diversifolia

2.’ Plants compact; leaves 5–10 mm diam…………………………………3

3. Low, sprawling shrublets, 30–50 mm high; leaves light green, usually suffused with red; leaf-pairs basally shortly connate for <c. 1 / of their 5 length; fruits with 6 locules…………………………………. …. 2. D. bella

3.’ Erect, densely branched shrublets, 150 (−200) mm tall, to 200 mm diam.; leaves dirty green; leaf-pairs basally connate for c. ⅓ of their length; fruits with 7(8) locules……….………....…... 3. D. kwaganapensis