Aspalathus usnoides C.H.Stirt. & Muasya, 2016

Stirton, C. H. & Muasya, A. M., 2016, Seven new species and notes on the genus Aspalathus (Crotalarieae, Fabaceae) *, South African Journal of Botany 104, pp. 35-46 : 39-40

3.3. Aspalathus usnoides C.H.Stirt. & Muasya , sp. nov.

Type: South Africa. Eastern Cape Province, Steytlerville (3324): Kareedouw, north of town and Kouga river (− CC), 31 Oct. 2011, Euston-Brown 1584 ( BOL, holo.!; E!, K!, MEL!, MO!, NBG!, NY!, P!, PRE!, S!, iso.) .

Erect willowy shrub or small tree, up to 5 m tall, reseeder. Stem up to 6 cm diameter, bark grey; branches long, arcuate, pendulous; young branches villous, older branches yellowish with grey reticulations. Leaves arranged in clusters of up to 12 leaflets. Lea fl ets 10–12 mm long, linear, soft, mostly incurved, covered with silvery-green, appressed pubescence. In fl orescences unifloral, on lateral short shoots, scattered along each branchlet. Flowers 8–9 mm long, lemon yellow, hidden among leaves or slightly protruding; pedicel 2 mm long, tomentose; bract 1 mm long, linear, pubescent; bracteoles 1 mm long, filiform. Calyx globose-campanulate, appressed villous; lobes narrowly triangular to linear, 5.5–6.0 mm long, soft; tube 2 mm long, twice shorter than lobes. Standard blade 8.5 × 6.6–7.0 mm, broadly ovate, margin ciliate, emarginate, back hairy throughout, upper front also hairy; claw 2 mm, broad, curved. Wing blades 4.0 × 1.0– 1.3 mm, glabrous, tip twisted and recurved; petal sculpturing comprises 3–4 rows of 50–60 small lunate costal and transcostal pockets covering the entire surface except for a central raised ridge along the midline; claw <2 mm, strongly recurved. Keel petals 5.0 × 1.5 mm, blades fused, tomentose along lower margin, auriculate, upper margin almost straight, lower convex, pocketed; claw 2 mm long, ribbon-like. Androecium 5 mm long with 5 basifixed and 5 dorsifixed, versatile anthers. Pistil 8 mm long; ovary 2–3 mm long, shaggy, ovules 2; style upcurved, hairy along upper margin to point of flexure. Fruits 4.0 × 2.5 mm (immature), hairy, style persistent, obliquely ovate; seeds unknown. Fig. 4.

3.3.1. Etymology

The specific epithet usnoides alludes to the distinctive drooping branches reminiscent of the lichen Usnea Dill. ex Adans. (Old Man's Beard). The silvery grey branches are very flimsy and wave around in the wind in a similar fashion to Old Man's Beard hanging in trees.

3.3.2. Diagnostic characters

Aspalathus usnoides is a very striking species that falls into Dahlgren's (1988) Group 34: Laterales. The species is similar to A. kougaënsis (Garab. ex R.Dahlgren) R.Dahlgren , but differs in its tall pendulous tree-like habit up to 5 m (versus ascending or spreading branches to 2 m) tall; leaves have appressed pubescence (versus villous to lanate); calyx lobes 5.5–6.0 mm (versus 1.5–3.0 mm) long; flowers lemon yellow (versus light yellow); and fruits broadly ovate (versus broadly lanceolate).

3.3.3. Distribution and habitat

Aspalathus usnoides is known from a few populations on the lower, south facing slopes of the Kouga Mountains to the north of Kareedouw in the Eastern Cape Province ( Fig. 5 ). The type collection is from Moordenaarskloof on the farm Jammers Fontein 119. A further collection was subsequently made on the neighbouring farm Brandkraal 219. This was from a large population on the steep south facing slopes above the Kouga River . The underlying rock is Peninsula Formation Quartzitic Sandstone.

Aspalathus usnoides is found in Kouga Grassy Sandstone Fynbos (FFs 28) ( Rebelo et al., 2006). It is restricted to 300–400 m altitude, and has only so far been seen on steep south facing slopes within this altitudinal range. There does not appear to be anything particularly special about its habitat requirements, and it is quite probable that the species will be found in several other localities along the south facing slopes above the Kouga River. Common species that grow together with this plant include Protea repens (L.) L., P. neriifolia R.Br. , Leucadendron salignum P.J. Bergius , Capeochloa arundinacea (P.J. Bergius) N.P. Barker & H.P. Linder and Hypodiscus striatus (Kunth) Mast.

3.3.4. Conservation status

Douglas Euston-Brown (personal communication) assessed this species as endangered (B2b, c; D2) under the IUCN Red list categories and criteria ( IUCN, 2001).

3.3.5. Additional material studied

South Africa, Eastern Cape: 3324 (Graaff Reinett): Rust en Vrede 4 × 4 track (− CA), 26 Aug. 2010, Schafer 2928 ( BOL) ; above Kouga River en route to Suuranys (− CD), 16 Feb. 2014, Stirton and Muasya 13,861 ( BOL, GRA, K, NBG, MO, NMMU, PRE, S) ; Guernakop, Kouga Mountains (− CD), 12 Jul. 1985, Vlok 937 ( NBG) ; Kareedouw, next to road on way to Nooitgedacht Farm, north of Kouga River , Moordenaarskloof (− CD), 27 Sep. 2011, Euston-Brown 1384 ( BOL, NBG) .

Figures

Fig. 4. Aspalathus usnoides.(A) habitat and colony; (b) flowering branches; (C) front view of flower; (D) habit; (E) side view of flower.

Fig. 5. Known distribution of Aspalathus barbigera (open circle), A. eriocephaloides (cross), A. eustonbrownii (black circle), A. macrocarpa (grey square), A. modesta (black square), A.nickhelmei (black triangle) and A. usnoides (grey circle) in Western and Eastern Cape Provinces.