Ruschia joubertiniana 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 : 149-151

1 Ruschia joubertiniana Klak sp. nov.

( Fig. 6 )

Type: South Africa, Eastern Cape, Willowmore (3323), near Joubertina , Kouga Wilderness , Farm Kleinrivier , (-DB), 7 Jan 2008, 500 m a.s.l., Klak 1589 ( BOL, holo, barcode: 46184 ; NBG, iso) .

Diagnosis: Differs from all other species in Ruschia by the 11-12 locules of its capsules (5-8 in all other Ruschia ). It differs from Erepsia since the end of the placenta is detached in the capsule and forms a hood (end of placenta not detached in Erepsia ) and by the absence of a hypanthium (present in Erepsia ).

Erect, sparsely branched, succulent shrub to 40 X 30 cm, with erect branches to 35 cm tall, becoming woody with age, basal branches 6-7 mm diam., internodes 20-30 X ± 2.5-3 mm, brown, older one’ s grey. Leaves opposite, triquetrous, with sharp tips, glaucous, with dark dots, erect to spreading, joined to the stem in the lower third of their length for 3-9 mm, and curved outwards towards their bases, thus forming a triangle between the two opposite leaves, keels cartilaginous, some with finely serrulate keel, epidermis smooth, 20-27 mm long, 5-6 mm broad and thick. Flowers solitary, 25-40 mm diam., pedicels erect, 7-20 mm long, bracts succulent, leaf-like; sepals 6, succulent, 3 with membranous wings; petaloid and filamentous staminodes numerous, filiform, curved over the centre of the flower, petaloid staminodes pink, 10.5 X 0.7 mm, shortest petals to ca. 5 mm long, filamentous staminodes white, papillate at base, 4 X 0.1-0.2 mm, stamens about as long as filamentous staminodes, papillate at base, in 3-4 rows, pollen white; stigmas 10-12, green slender, smooth, 1.5 X 0.2 mm, top of ovary flat, nectary forming conspicuous green crenulated ring. Capsule 10- to 12-locular, 10-14 mm diam., top dome shaped and raised to 5 mm, with low rims, lower part bowl- to funnel-shaped to 5 mm deep, without wings, closing bodies absent, placenta forming a hood, covering membranes curved up at ends, but without additional closing device below, keels parallel first then diverging, valve wings absent. Seeds light brown to ochre, 0.8-0.9 X 0.6-0.7 mm, slightly colliculate.

3.1.15. Distribution and ecology

Ruschia joubertiniana is known only from the type locality at Kouga Wilderness ( Fig. 7 ). It is, however, likely that this species occurs in similar habitats on neighbouring mountains. It prefers sandstone soil among fynbos. The species is rare in mature fynbos, where it grows among tall shrubs such as species of Protea. However, the species may form large populations after fires, when the soil is enriched and no shading or competition for nutrients occurs from other taller shrubs. Plants were collected at 500 m a.s.l. Flowering occurs in October.

3.1.16. Distinguishing features and relationships

Ruschia joubertiniana is characterized by 10- to 12-locular fruits, solitary showy pink flowers with numerous filiform petaloid staminodes. Typically, the shorter inner petals and the filamentous staminodes curve over the center of the flower, but no hypanthium is present. The leaves are joined to the stem and usually curve outwards towards their bases. Thus, the leaves are not joined to each other to form a sheath as in subg. Tumidula . This arrangement of leaves is typical for subg. Cymbifolia (see also discussion under section C for Ruschia aristata (L.Bolus) L.Bolus ). The high number of locules distinguish it from other members of subg. Cymbifolia , which are 5- to 9- locular.

3.1.17. Etymology The epithet refers to the area where this species was discovered.

3.1.18. Conservation status

The distribution of Ruschia joubertiniana is insufficiently known. It is possible that the species is rare, so that increased fire frequencies may form a threat. However, the agricultural use of the area is severely limited by its a rugged and dissected nature. We recommend a conservation status of data deficient (DD).

Figures

Fig. 6. Ruschia joubertiniana. A. Habit. B. Flower.C. Side view of closed (l) and top view of open fruit (r). D. Seeds.

Fig. 7. Distribution of species of Ruschia subg.Cymbifoliae. R.joubertiniana (triangle), R.knysnana (circle) and R.aristata (star).