Lebeckia gracilis, Eckl. and Zeyh.

le Roux, M. M. & Van Wyk, B. - E., 2007, A revision of Lebeckia sect. Lebeckia: The L. sepiaria group, South African Journal of Botany 73 (1), pp. 118-130 : 126-127

4.3. L. gracilis

L. gracilis Eckl. and Zeyh., Enum.: 192 (1836); Benth. in Hook., Lond. J. Bot. 3: 358 (1844).

Type: South Africa, “Zwartkopsrivier” [3322 CD], Ecklon and Zeyher 1336 ( SAM!, specimen in middle of the sheet, lectotype, designated here ; P!, S!, isolectotypes) .

L. sepiaria auct. non (L.) Thunb .: Eckl. and Zeyh., Enum.: 191 (1836); Harv. in Harv. and Sond., Fl. Cap. 2: 86 (1862); Goldblatt and Manning, Cape Plants, Strelitzia 9: 493 (2000). [Harvey cited a Thunberg specimen (Thunberg s.n. sub Herb. Thunberg 16422) which is indeed this species. However, Thunberg based his description on a specimen from Cape Town “Leeuwenberg”, but he explicitly cited Spartium sepiarium of Linnaeus, q.v.]

L. ambigua E. Mey., Com. : 34 (1836), pro parte minore.

Erect, glaucous suffrutex, 0.15 − 0.8 m in height. Leaves simple, acicular, articulated near the middle; leaf density 3–6 per 10 mm length of stem. Inflorescences terminal, 44–172 mm long; rachis furrowed; flowers numerous, relatively dense (5–7 per 10 mm length of rachis), relatively small in size (6–8 mm long); pedicel 1.5–3.0 mm long; bract lanceolate, acute, ± 2 mm long; bracteoles triangular, acuminate, ± 1 mm long. Calyx 2.5–4.5 mm long, tube 1.5–3.5 mm long, lobes 0.7–1.5 mm long; ± equally lobed; lobes deltoid, tips minutely pubescent inside. Standard widely oblong to suborbicular or obovate, 4.0–6.5 × 2.0– 3.5 mm; apex obtuse; claw 1.5–2.5 mm long. Wings oblong, longer than the keel, 4.0–6.5 × 1.0– 2.5 mm, with 11–14 rows of sculpturing; apex obtuse; claws 1.5–2.0 mm long. Keel rostrate, 5–6 × 1.5–2.5 mm, sometimes with pockets; claws 1.5–2.5 mm long. Pistil subsessile; ovary 5.5–7.5 × 0.6–0.8 mm long, linear; ovules many (9–11); style 1.5–3.5 mm long, curved upwards. Pods linear, straight or very slightly falcate, up to 37 × 2–3 mm; dehiscent; semi-terete; fruit wall thin, membranous. Seeds reniform-orbicular, ± 1.8 × 1.5 mm, rugose, pale brown, mottled dark brown to black; hilum dark brown ( Fig. 9 ).

4.3.1. Diagnostic characters

L. gracilis is similar to L. ambigua but differs in its calyx that is ± equally lobed and with the lobes shorter than the tube (calyx subequally lobed and the lobes as long as the tube in L. ambigua ) ( Fig. 9 ). L. gracilis also differs from L. ambigua in its shorter and more congested racemes. The two species are allopatric.

4.3.2. Distribution and habitat

L. gracilis has a distinctively coastal distribution, from Bredasdorp in the Western Cape Province eastwards to Port Elizabeth in the Eastern Cape Province ( Fig. 10 ). All known localities are below 300 m altitude. Those in the west experience winter rainfall, while those in the east (around Port Elizabeth) have a higher proportion of summer rain. Plants grow in deep sandy soil.

4.3.3. Specimens examined.

– 3322 (Oudtshoorn): Fairy Knowe (– DC), Guillarmond 8257 ( PRE) ; Rondevlei (– DC), Sachse 670 ( PRE) ; Wilderness (– DC), Van Niekerk 223 ( BOL) ; Ruigtevlei at Zwart River (– DD), Fourcade 1534 ( BOL, NBG, PRE) . – 3324 (Steytlerville): Zwartkopsrivier (– DC), Ecklon and Zeyher 1336 ( P, S, SAM) , Zeyher 2293 ( P, S) ; Gamtoos River (– DD), Gillett 2361 ( NBG) .

– 3325 (Port Elizabeth): Humewood (– DC), Paterson 773 ( BOL) .

– 3420 (Bredasdorp): De Hoop (– AD), Morley 139 ( PRE) ; Melkbosheuwel (– BC), Burgers 2461 ( NBG) ; Potberg area (– BC), Derdejaarsekskursie 84/C10 ( NBG) ; Potberg (– BC), Esterhuysen 23259 ( BOL) ; De Hoop (– BC), Fellingham 701 ( PRE) ; The Poort (– CA), Henderson 1829 ( NBG), Morris 268 ( NBG) ; Bredasdorp Poort (– CA) , Heginbotham 163 ( NBG) .

– 3421 (Riversdale): Oude Tuin near Albertinia (– AB), Muir 1852 ( BOL, PRE) ; Stilbaai (– AD), Jordaan 18607 ( NBG) ; Stilbaaihoogte (– AD), Bohnen 7617 ( NBG) , Le Roux, Boatwright , Magee and Van Wyk 17 ( JRAU) .

– 3422 (Mossel Bay): Brak River (– AA), Young 5514 ( BOL) ; Belvedere (– BB), Duthie 510 ( NBG) ; Goukamma (– BB) , Wurts 2234 ( NBG) .

– 3423 (Knysna): Between Knysna and Plettenberg Bay (– AA), Pappe s.n. ( S, SAM) ; Plettenbergbaai (– AB), Anon s.n. sub STEU 13540 ( NBG) .

– 3425 (Port Elizabeth): Schoenmakers Kop (– AB), Story 3654 ( PRE) .

Figures

Fig. 9. Morphology of Lebeckia gracilis: (a) Lateral view of flower; (b) abaxial view of bract and bracteoles; (c) abaxial view of calyx with the upper lobes to the left; (d) standard petal; (e) wing petal; (f) keel petal; (g) anthers; (h) long, basifixed anther, carinal (intermediate) anther and short, dorsifixed anther; (i) pistil; (j1 – j2) lateral view of pods; (k) cross section of pod; (l) leaf. Vouchers: (a) from Heginbotham 163 (NBG); (b, e) from Esterhuysen 23529 (BOL); (c, f, g, h, i) from Bohnen 7617 (NBG); (d) from Leighton 1894 (BOL); (j1) from Hutchinson 1478 (BOL); (j2) from Ecklon and Zeyher 1336 (S); (k) from Le Roux, Boatwright, Magee and Van Wyk 17 (JRAU); (l) from Wurts 2234 (NBG). Scale bars: 1 mm.

Fig. 10. Known distribution of Lebeckia gracilis.