Drosanthemopsis bella Klak, 2018

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 : 78

2. Drosanthemopsis bella Klak , sp. nov.

Type: South Africa, Northern Cape, Hondeklipbaai (3017): farm Leeuvlei near Spioenkop , (− DA), 140 m, 26 Sept. 2013, Klak 2309 ( BOL, holo.; K, iso) .

Low, sprawling, succulent perennial shrub 30–50 mm high, 300– 400 mm diam., spreading branches 150–200 mm long, stems woody, distinct long and short shoots present, internodes brown, to 25 mm long, young internodes covered with papillae, visible as white dots in dried material, becoming smooth with age. Leaves fresh green to dirty green and reddish suffused, boat-shaped to club-shaped, top flat, keels indistinct, spreading widely, leaf-pairs isophyllous to slightly anisophyllous, basally shortly fused, sheath c. 4 mm long, free parts 11–18 mm long, 8–10 mm broad and thick, keel inconspicuous; epidermis with large bladder cells with thickened outer walls, cells 0.2–0.3 mm diam., ± circular to polygonal, bladder cells with flat top covered with tiny protrusions on their surface ( Fig. 5C ). Flowers solitary, terminal, petaloid staminodes pink becoming white towards the centre or white throughout, filamentous staminodes absent or very few, filaments white, 30–40 mm diam., pedicels 6–14 mm long; sepals 6, succulent, two larger and opposite, the remaining ones smaller. Fruit a hygrochastic capsule, old capsules grey, capsule as seen from above ±circular, 7–9 mm diam., top flat with rims raised, lower part funnel-shaped; locules 6; borderline between expanding keels and expanding sheet ±distinct, keels broad and only slightly diverging; covering membranes thin and without any additional closing devices, ±covering the locule, small closing bodies infrequently formed, valve wings broad. Seeds with testa translucent to ochre, almost smooth, c. 0.7 × 0.5 mm.

Distribution and ecology: Drosanthemopsis bella is known from a single population near Garies in southern Namaqualand (Map 6). The plants grow in heavy loam over weathered shales in otherwise almost bare patches of quartz-gravel. Flowering takes place between August and September.

Diagnostic characters: Fruit and epidermal features (see diagnostic characters for D. kwaganapensis ) clearly place D. bella within Drosanthemopsis . Only D. vaginata and D. bella form low cushions or mounds ( Fig. 1B&C ), whereas the other two species are erect shrublets. In contrast to D. vaginata , which has grey leaves, the leaves are light green with a red tinge in D. bella . The diameter of the epidermal cells is smaller in D. vaginata than in D. bella ( Table 1 ).

Etymology

The epithet “ bella ” is derived from the Latin meaning pretty and alludes to the showy flowers.

Conservation status

The species is known only from one location where the population covers a total area (Area of Occupancy; AOO) of less than 1 ha. The total number of plants is estimated at between 200 and 300. The area is grazed by small livestock (mainly sheep), but the plants did not appear to be affected by this. According to IUCN 3.1 criteria ( IUCN, 2001) the species is classified as VU D1.

Additional specimens examined:

South Africa. NORTHERN CAPE: 3017 (Hondeklipbaai): 30 km W of Garies, farm Soutfontein 436, N of Outeep river, (−DA), Helme 8058 (NBG).

Figures

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).

Fig. 1. Habit, flowers and fruits of Jacobsenia and Drosanthemopsis. A. J.hallii, near Komkans, Klak 2293 (BOL), with dirty green leaves.B. J.vaginata (=D. vaginata), at Riethuis,with gray leaves.C & D. D. bella, at Spioenkop, Klak 2309 (BOL), flowers magenta with white centre (C) or white (D).E & F. D.kwaganapensis, at the Kwaganapriver, Klak 2379 (BOL),showing the dirty green leaves (E) and white flowers (F).G & H. Top view of open (left) and side view of closed (right) fruit of Drosanthemopsis. G. D. bella, Klak 2309 (BOL); H. D.kwaganapensis, Klak 2573 (BOL); Scale: Distances between white lines indicate 1 mm.