Ruschia rupestris Klak, 2023

Klak, Cornelia, Hanáček, Pavel & Bruyns, Peter V., 2023, Six new species of Ruschieae (Aizoaceae) and further notes in Ruschia, South African Journal of Botany 156, pp. 144-161 : 151-152

1 Ruschia rupestris Klak sp. nov.

( Fig. 8 )

Type: South Africa, Western Cape, 5 km east of Seweweekspoort on road to Bosluiskloof (-AD), 1110 m a.s.l., 3 Apr 2021, Klak 2854 ( BOL, holo, barcode: BOL0232474 ) .

Diagnosis: Differs from Ruschia altigena by a more upright habit and height of 15-25 cm (prostrate and <15 cm tall in R. altigena ). In addition, in R. rupestris endocarpal closing bodies are missing and the placentas form broad open hoods (only small closing bodies present in R. altigena ).

Clump-forming dense succulent shrub 15-25 X 30-50 cm, with some prostrate branches and with erect flowering branches, basal part very woody, to 9 mm diam, internodes 4-15 X ± 4 mm, black or grey. Leaves opposite, trigonous, with rounded keel, tips pointed, dark, dirty green, spreading, fused into a sheath to 9 mm long, sheath without a line, 12-25 (-36) mm long, 4-6 mm broad and thick, old, blackened leaves drying up and persisting on plant for several years. Flowers solitary, 15-20 mm diam., pedicels short, 6-8 mm long, bracts at base of pedicel, to 4 X ± 1 mm, sepals 5.7-10 mm long, subequal, slightly succulent, without membranous margins; petaloid staminodes magenta, 2-3-seriate, ± same length, 6.5-9 X 0.7-0.9 mm, lanceolate to obtuse, filamentous staminodes few, collected in the center and about the same length as the stamens, 4.5-5.0 X 0.1-0.2 mm; stamens numerous, outer stamens ± 5 mm long, in 4-5 rows, papillate at base, pollen white; stigmas 5, short, 3.2-3.5 mm long, yellowish, top of ovary raised in the center to ± 1.2 mm; nectary forming green, crenulated ring. Capsule 5-locular, 6-8 mm diam., top raised to 2 mm, with low rims, lower part 4 mm deep and top-shaped, covering membranes firm, with inconspicuous ridge below, keels slender, widely separated at their bases, slightly lacerated in upper parts, long so that valves open into a horizontal position, closing bodies absent, placenta forming broad open hood detached at the top and from which funicles arise, valve wings absent. Seeds ochre, finely colliculate to almost smooth, 0.6-0.7 X 0.5-0.6 mm.

3.1.19. Distribution and ecology

The species is known from the Montagu and Ladismith districts ( Fig. 4 ), on sandstones of the Witteberg-Series, either on lower slopes or on flat rocky areas, typically in the transitional area from sandstones to shales. These spots, at altitudes from 820 to 1060 m a.s.l, are rich in other succulent species. Flowering occurs from November to December.

3.1.20. Distinguishing features and relationships

Ruschia rupestris is closely allied to R. altigena . The two species differ in their habit: R. rupestris forms cushions with some prostrate branches and with erect flowering branches to 25 cm tall ( Fig. 8A, B ), whereas older plants of R. altigena form dense, spreading mats ( Fig. 8C ), where the flowering branches are less than 15 cm tall. Ruschia altigena occurs at higher altitudes, from ± 1300 to 1700 m a. s.l., on rocky sandstone outcrops within fynbos, where few other succulents are found. Ruschia karrooica (L.Bolus) L.Bolus , which is known from Matjiesfontein, near Laingsburg, may be a further close relative. The latter species has an erect habit, but shares the highly fused leaves, solitary flowers and broad open hoods, instead of closing bodies.

3.1.21. Etymology

The epithet refers to the rocky habitats to which the species is confined.

3.1.22. Conservation status

Due to its preference for rocky habitats which are not arable, the absence of any mining activities in the area and the relatively wide occurrence, we suggest a status of Least Concern (LC).

3.1.23. Additional specimens investigated

South Africa. WESTERN CAPE: 3320 (Montagu): Witteberg , north aspect (-BC), 10 Nov. 1935, ± 3000 ft, F.M. Leighton s.n. ( BOL, barcode 39865 ) ; Farm Varsbokkraal, entrance to Zuurkloof (-BD), 857 m a.s.l., 4 Apr 2021, Klak 2865 ( BOL) ; 9 Aug 2013, Bruyns 12585 ( BOL) ; 3321 (Ladismith): Farm Vleiland , entrance to kloof (-AC), 820 m a.s.l., 26 Jun 2021, Klak 2871 ( BOL) ; Bosluiskloofpass (-AD), 1054 m a.s.l., 2 Sep 2008, Klak 1716 ( BOL) ;

Figures

Fig. 8. Ruschia rupestris (A, B, E, F) and R. altigena (C, D, F). A. Habit. B. Leaves and fruits. C. Low spreading habit of older plants of R.altigena. D. Younger plants of R. altigena are similar in habit to R. rupestris. E. Side view of closed (l) and top view of open fruit (r). F. Seeds of R.rupestris (top) and R.altigena (bottom). The smaller size and lighter colour in R. rupestris can readily be seen.

Fig. 4. Distribution of new species of Ruschia: R.variabilis (circle), R.pseudocrassa (triangle), R.rupestris (inverted triangle).