Otholobium outrampsii C.H.Stirton & B.du Preez, 2021

Stirton, Charles H. & Du Preez, Brian, 2021, Otholobium outrampsii (Psoraleeae, Fabaceae) - a new species from the Western Cape, South Africa, Bothalia (a 5) 51 (2), pp. 1-5 : 1-2

1. Otholobium outrampsii C.H.Stirton & B.du Preez sp. nov., closely allied to O. curtisiae C.H.Stirt. & Muasya from which it differs in having green hairy stems with sparse, small, round, yellowish glands (versus purplish-green, hispid stems encrusted with prominent orange, urn-shaped pustules); semi-conduplicate,

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minutely glandular, pilose, narrowly elliptic to narrowly obovate leaflets, apex attenuate (versus flat, prominently glandular, glabrous, oblanceolate to oblong leaflets, apex apiculate); sessile pseudo-capitate 9–12-flowered terminal inflorescences borne on short seasonal shoots (versus capitate shortly pedunculate 3–6-flowered inflorescences borne in upper axils); flower triplets subtended by a flabellate bract (versus oblong bract); and accrescent calyx (versus non-accrescent calyx). TYPE: SOUTH AFRICA, Western Cape , lower northern slopes of Fouriesberg in Outeniqua Mountains, 3321DD, [33º48’20.002”S / 21º55’5.001”E, 530 masl], 13 Dec. 2013, Viviers & Vlok 367 (holotype PRE!) .

Prostrate to semi-erect shrublet 15–20 cm tall, resprout- er. Stems 1 to many, branching along the prostrate stems, branches smooth, hairy when young, glabrous when older, flowering shoots clustered in the upper axils of the new season’s growth, softly pilose, without urn-shaped pustules concentrated below leaves. Stipules 2.5–3.0 × 1.0 mm, persistent, appressed to recurving, subulate, hairy. Leaves digitately trifoliolate, inserted spirally, semi-erect, shortly petiolate; petioles 1.0– 1.5 mm long, petiolule 0.4–0.5 mm long, hairy; leaflets 8–10 × 2.0– 2.4 mm, the later produced leaflets slightly smaller and more densely hairy, rigid, semi-conduplicate, arching, narrowly elliptic to narrowly obovate, apex attenuate, base cuneate; terminal leaflet longer than laterals, symmetrical, laterals asymmetrical, glands sunken,scarcely visible with a 10× lens.Inflorescences pseudo-capitate in axils of short seasonal shoots, flowers in triplets, shorter than subtending leaves, comprising 3–4 triplets of flowers; each triplet subtended by a single 3 × 12 mm long, flabellate, oblong, multiveined bract, narrowing towards the apex, caducous; peduncle absent. Flowers white, pedicel 2.8–3.0 mm long; each flower subtended by a narrowly lanceolate hairy bract up to 3.5 mm long. Calyx 5 mm long, accrescent; lobes subequal, vexillar teeth shortest, lanceolate, carinal tooth 2–3× wider, broadly lanceolate, dark green and strongly ribbed, with 3 prominent dark green veins, teeth sparsely glandular, densely white pilose along margins, hairs patent; tube 2 mm deep, pale green. Standard 6.5–7.2 × 5.5–6.0 mm, glabrous, broadly ovate, emarginate, white, nectar guide an arc of dark purple flecks near base of blade, appendages present on lower inner face, low, parallel and separate; claw short ± 0.5 mm long. Wing petals 5.5–6.0 × 1.8–2.2 mm, blade broadly cultrate, white, scarcely auriculate, petal sculpturing present, upper basal and upper central comprising low parallel trans-costal ridges; claw ± 2 mm long, ribbon-like. Keel 4.2–4.5 × 1.5–1.6 mm, white with a dark purple discolouration on almost half of inner face of blade; claw ± 2 mm long, ribbon-like; Androecium ± 3.8 mm long, vexillar stamen free and bent at base; anthers alternately basifixed and medi-fixed; small nectarial ring present. Pistil ± 3.5 mm long, glabrous, ovary ± 0.9 mm long, 1-ovulate, covered in a few recurved stalked glands; style ribbon-like, glabrous, entasis broadest before the point of flexure; stigma penicillate. Fruits and seeds unknown. Figures 1 and 2 .

Figures

Figure 1. Otholobium outrampsii. A, habit of plant, 1/10th life size; B, fruiting shoot showing accrescent calyces, 10×; C, upper surface of terminal leaflet, 10×; D, lower surface of old leaflet, 8×; E, transverse section of leaflet, 20×; F, calyx opened out, outer face, 7.5×; G, side view of calyx, 8×. [Viviers & Vlok 367 (PRE)]. Artist Charles Stirton.

Figure 2. Otholobium outrampsii. A, flower front view; B, flower side view; C, flower ventral view; D, seasonal leaf adaxial surface; E, whole plant in habitat; F, flowering shoot. Photographs: B. du Preez.