Namaquanthus cephalophylloides Klak, 2001

Klak, Cornelia, Hanáček, Pavel & Bruyns, Peter V., 2023, Two New Species of Aizoaceae (Ruschieae, Ruschoideae) from the Cape, South Africa., Haseltonia 29 (1), pp. 16-23 : 21-22

2. Namaquanthus cephalophylloides Klak sp. nov. (Fig. 5)

Type: South Africa, Northern Cape, Kwaganap River, between Port Nolloth and Grootmis (2917 AC), 19 Jul. 2021, 150 m, Klak 2917 ( BOL, holo.) .

Differs from N. vanheerdei by its much smaller stature (to 10 cm tall as opposed to 30 cm tall in N. vanheerdei ). In addition, the stalks of maturing fruit bend downwards and the fruit finally detach from the plant along a preformed incision, whereas the fruit remain erect and attached to the fruit-stalk in N. vanheerdei .

Dwarf, clump forming more or less stemless perennial succulent, with only basal part very woody, <10 × 15 cm. Leaves opposite, ascending, ± free to their bases, finger-shaped, with upper side only slightly flattened, 45–60 × 8–13 mm, tips obtuse. Flowers solitary, 45–50 mm diam., pedicels erect to slightly bent, bending further down as fruit matures, to 45 mm long, bracts succulent and positioned near the base of plant and thus hidden between the leaves; sepals 4, subequal, succulent, flat and broad, ± 8.5 × 8.2 mm, 2 slightly narrower to 5 mm broad and with membranous margins; petaloid staminodes brilliant magenta, paler towards the center, 2- to 3-seriate, ± same length, 22–24 × 2.8 mm, lanceolate to obtuse, filamentous staminodes absent; stamens numerous, filaments 3.5–5.2 mm long, inner ones shortest, white, papillate at base, in 3–4 rows, pollen white; stigmas 8–9, short, feathery, 2.5 mm long, yellowish, top of ovary slightly raised in the center; nectary forming green, crenulated ring. Capsule 8- to 9-locular, detaching from pedicel once mature, 10 mm diam., top raised to 3 mm, with low rims, lower part 7 mm deep, rounded to bell-shaped, basally indented where pedicel attached, covering membranes thin and flexible, raised in the center, without additional closing-devices below, completely covering the locules, without closing-bodies, valve wings broad, ± rectangular. Seeds ochre, to 1.1 mm long, echinate with slender papillae.

DISTRIBUTION AND ECOLOGY

The species is only known from the Kwaganap River south-east of Port Nolloth, in the arid winterrainfall region of northern Namaqualand (Fig. 4). Here it occurs on shallow loamy soils overlaying gneiss with quartz-gravel on the surface. The species occurs at an altitude of around 150 m. It flowers between May and July. The similarly restricted N. vanheerdei is only known from north- and westfacing quartzitic slopes around 30 km east of Port Nolloth (Fig. 4).

DISTINGUISHING FEATURES AND RELATIONSHIPS

N. vanheerdei forms shrubs to 30 cm high and to 50 cm diameter, whereas N. cephalophylloides is a clump-forming dwarf shrub that does not exceed 15 cm broad. Both species of Namaquanthus have thick, finger-shaped leaves that are more or less free to their bases. However, in the new species the leaves are gray, almost white from a thick covering of wax, whereas N. vanheerdei has dark green leaves, which are typically partially blackened by a fungus or a lichen in their habitat (Fig. 2B). Furthermore, both species possess large bril- liantly colored, magenta, solitary flowers. However, the pedicels are erect and only reach 10 mm long in N. vanheerdei (Fig. 2), whereas they are to 45 mm long and curved in N. cephalophylloides (Fig. 5B). Unusual for N. vanheerdei is that the inner petals unfold only after several days, hiding the center of the flower in the beginning (Fig. 2C, D). Such slow opening of the flowers was not observed for N. cephalophylloides . Bolus (1954) reported the anthers and pollen to be deep purple for N. vanheerdei . However, our own observations revealed that some plants can also have yellow pollen (Fig. 2C), whereas the pollen is white in N. cephalophylloides . Noteworthy are the echinate seeds (Fig. 5E, F), which are common to both species. Unusual in N. cephalophylloides are the downward pointing fruits (Fig. 5A), which become detached once they are mature. This contrasts with most of the species in the Ruschioideae, where the fruits are retained on the plant for 1–2 years or longer. In Cephalophyllum , the tops of the fruits always point upwards and possess closing-bodies. Although papillate seeds are also found in Astridia , the fruits of Astridia have closing-bodies, which are absent in Namaquanthus . A possible close relative is the monotypic Enarganthe , which differs in its trigonous to clubshaped leaves and the pear-shaped, elongated, almost smooth seeds.

ETYMOLOGY

The epithet refers to the superficial resemblance of the new species to members of Cephalophyllum .

CONSERVATION STATUS

We consider this species to be rare, because of its specific habitat requirements. These are large patches of quartz-gravel close to the sea. A similar habitat at Grootmis near Kleinzee, did not contain this species. This contrasts with Drosanthemopsis kwaganapensis Klak , which is found at the type locality of N. cephalophylloides and also at Grootmis ( Klak et al. 2018). Given the isolat- ed nature and the high habitat-specificity of the known population, we recommend that it is considered Vulnerable and placed on the Red Data List of South African plants.