Aspalathus eustonbrownii 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 : 41-42

3.5. Aspalathus eustonbrownii C.H.Stirt. & Muasya , sp. nov.

Type: South Africa. Western Cape Province, Bredasdorp (3420), Skeiding Farm (− DD), 19 June 2011, Euston-Brown and Curtis 1094 ( BOL, holo.!; NBG, iso.!) .

An erect shrub up to 1.5 m tall, resprouter; young branches reddish brown with silvery sericeous covering. Leaves arranged in tight clusters of up to 12–15 leaflets. Lea fl ets 12–15 mm long, piniform, straight or slightly curved, with appressed silvery sericeous pubescence. In fl orescences unifloral, on lateral short shoots, occasional along each branchlet. Flowers 10 mm long, dark yellow, hidden among leaves; pedicel absent or <1 mm long, tomentose; bract 4 mm long, linear, pubescent; bracteoles 3 mm long, filiform. Calyx campanulate, appressed villous; lobes 2.6–2.8 mm long, broadly triangular, swollen, stiff, apex rigid; tube 3 mm long, longer than lobes, carinal tooth larger than other teeth. Standard blade 6 × 5 mm, broadly ovate, yellow ageing orange, with russetcoloured triangular nectar patch, margin ciliate, emarginate, back hairy throughout, upper front apical part also hairy, apex large and sharply recurved, rigid; claw 2 mm, curved. Wing blades 4.5 × 1.0– 1.2 mm, glabrous except for hairy tips, lower surface strongly inrolled and held tight up against standard petal; petal sculpturing comprises 2–3 indistinct rows of up to 40–50 mostly transcostal lamellae and some costal pockets over two thirds of the upper outer surface; claw 2 mm, recurved. Keel petals 4.0 × 4.2 mm, blades fused, lunate, obtuse, blade glabrous, scarcely auriculate, upper margin slightly convex, lower convex, pocketed; claw 2 mm long, flattish. Androecium 6.5 mm long with 5 basifixed and 5 dorsifixed, versatile anthers. Pistil 6 mm long; ovary 2 mm long, long-haired on ovary, ovules 2; style almost straight, glabrous. Fruits 9 × 6 mm, shaggy, style persistent, obliquely ovate; seeds unknown. Fig. 7.

3.5.1. Etymology

The specific epithet eustonbrownii honours the Cape Town based botanist Douglas Euston-Brown who has discovered a number of rare and previously unknown legumes from the Western and Eastern Cape Provinces.

3.5.2. Diagnostic characters

Aspalathus eustonbrownii is a distinctive species that falls into Dahlgren's (1988) Group 34: Laterales. The species is similar to A. longifolia Benth. , but differs in its leaflets 12–15 mm (versus 25–40 mm) long; calyx lobes 2.6–2.8 mm (versus <0.5 mm) long; and fruits broadly ovate (versus narrowly ovate).

3.5.3. Distribution and habitat

Aspalathus eustonbrownii is endemic to Swellendam Silcrete Fynbos (FFc 1) and Eastern Rûens Shale Renosterveld (FRs 13) ( Fig. 5 ; Rebelo et al., 2006). The vegetation types in which it is found are poorly collected. Although locally frequent in the area in which it occurs it is heavily grazed. It occurs on well-drained sandy loams on gentle south facing slopes of rocky silcrete “koppies” in between ploughed lands. Other Aspalathus species recorded growing in this habitat include A. microlithica C.H.Stirt. & Muasya , A. cliffortioides R.Dahlgren , A. laricifolia P.J.Bergius and A. millefolia R.Dahlgren. Flowering is atypical for Aspalathus and takes place from February to July which is well outside the general flowering season of the genus, which occurs between August and December. It occurs at an altitude of about 300– 320 m. Sterile material presumed to be this species has been found on Nysty Farm, 40 km north of Bredasdorp, along the San Souci Road, but needs confirmation.

3.5.4. Conservation status

Aspalathus eustonbrownii is locally common where it occurs but none of its distribution occurs in a protected area. Over-grazing is a threat which could be mitigated by fencing off some of the area as a protection against grazing. Populations found along roadsides are in greatest threat as the Road's Department authorities have a policy of clearing all vegetation from what in the Overberg are the remaining remnants of natural vegetation in a sea of wheatlands.The rocky habitat on silcrete “koppies” in between ploughed lands suggests that this species will be found in several other locations in the surrounding area. Douglas Euston-Brown (personal communication) assessed this species to be endangered (B2b, c, D2) under the IUCN Red list categories and criteria ( IUCN, 2001).

3.5.5. Additional material studied

South Africa. Western Cape: 3420 (Bredasdorp): Uitvlugt Farm, Heidelberg (− CA), 7 Sep. 2013, Curtis 188 ( BOL) ; near Ma se Kop Farm, along Buffeljags – Suurbrak Road , off Swellendam – Heidelberg Road (− CA), 2 Feb. 2013, Stirton and Curtis 13,792 ( BOL, NBG, PRE) ; Skeiding Farm (− DD), 3 Feb. 2013, Stirton and Curtis 13,795 ( BOL) .

Figures

Fig.7. Aspalathus eustonbrownii. (A)habit;(B) leaf cluster;(C) flowering branches;(D) frontview of flower;(E)portion offloweringshoot;(F)mature flower in shoot axil;(G)young fruit.

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.