Chamaecrista biensis, (Steyaert) Lock, Kew Bull.

Musandiwa, Liada, Magee, Anthony R. & Boatwright, James S., 2022, A Taxonomic Revision of Chamaecrista (Caesalpinioideae, Cassieae, Cassiinae) in Southern Africa, Systematic Botany (Basel, Switzerland) 47 (4), pp. 992-1011 : 998-999

2. CHAMAECRISTA BIENSIS (Steyaert) Lock , Kew Bull. 43(2): 335 (1988);

Brummitt in Fl. Zambesiaca 3(2): 130 (2007). Cassia katangensis (Ghesq.) Steyaert var. biensis Steyaert. , Bull. Jard. Bot. Etat 20: 260 (1950). Cassia biensis (Steyaert) Mendonça & Torre. , Bol. Soc. Brot. Ser. 29(2): 33 (1955); Schreiber in F. S.W.A. 59: 11 (1956); Gordon-Gray in F.S.A. 16(2): 100 (1977).

TYPE: ANGOLA. Bie Province, Dec 1932, Gossweiler 9 (holotype: BR [ BR08918918 ]–image!. ).

Perennial herbs, to 0.5 m tall. Stems producing multiple branches from a woody rootstock, prostrate or decumbent, pubescent, with small curved appressed hairs. Leaves paripinnate, 10–65 × 5–20 mm, oblong to linear oblong, tapering slightly distally; stipules straight, 5–10 mm long, base oblique, apex acuminate; rachis channelled; extrafloral nectaries on petiole, circular, concave, ± 0.3 × 0.2–0.5 mm, attached with short stalk. Leaflets 6–25-jugate, 5–10 × 1–2 mm, linear oblong, base oblique, apex apiculate, margin ciliate, midrib strongly excentric towards anticous margin. Inflorescence axillary, 1–2 flowered; flowers 5–10 × 4–6 mm, bract ± 3 mm long, base oblique, apex acuminate; bracteoles 2, glabrous, towards top of pedicels. Pedicels with short, straight or curved hairs, 15–20 mm at flowering, 20–25 mm at fruiting. Sepals 5, ovate, 4–8 × 2–3 mm, pubescent on the outer surface. Petals 5, obovate 7–10 × 3–5 mm, bright yellow. Stamens 10, straight or slightly curved, anthers vary in size, often in two (5 medium and 5 large) or three series (3 small, 4 medium, and 3 large), 2–7 mm long, filaments very short, 1 mm long. Ovary 6–9 mm long, densely covered with white hairs, slightly curved or straight, glabrous. Pods 20–50 × 3–5 mm, flattened, straight or curved, with small curved suppressed hairs. Seeds 2.5–4.0 × 1–2 mm, rhomboid, flattened, brown to light brown.

Diagnostic Characters — Chamaecrista biensis shares a low growth form and leaf structure with C. capensis (particularly C. capensis var. capensis ). However, C. biensis can be distinguished by its extrafloral nectaries on the petiole attached by a very short stalk, ± 0.3 × 0.2–0.5 mm ( Fig. 3C ) (well developed in C. capensis ) and short pedicels 15–25 mm (up to 45 mm in C. capensis ) bearing small flowers 5–10 × 4–6 mm (large flowers 10–17 × 5–15 mm in C. capensis ).

Distribution and Ecology —The species is widespread from the north-eastern parts of Namibia, extending to South Africa with a wide distribution in the North West Province through to the Northern Cape, Emalahleni (Witbank) in Mpumalanga and along the drier northern parts of the country across to Botswana ( Fig. 5 ). Chamaecrista biensis grows on sandy or well-drained soil at elevations below 1530 m. Flowering from October to March.

Additional Specimens Examined — Namibia. —1817 (Tsitsabis): along the main road from farm Sachsenheim to Oshivelo (–CA), 3 Apr 2002, Uiras MU547 ( PRE) . 1819 (Karakuwisa): Cigarrete, NE of Karakuwise (–BA), 25 Jan 1953, Maguire 2331 ( NBG) . 1918 (Grootfontein): Taranaki, 80 km from Grootfointein on road to Rundu (–BA), 5 Mar 1995, Germishuizen 7510 ( PRE) ; on road to Sonap Research Station, 4 km from Taranaki farm (–BB), 6 Mar 1995, Germishuizen 7617 ( PRE) . 1919 (Kanovlei): on road to Tsumkwe, 50 km NE of Grootfointein (–AC), 7 Mar 1995, Germishuizen 7643 ( PRE) . 1920 (Tsumkwe): southern Bushmanland, Revele BL 3.2 km W of Kremetartkop (–DD), 26 Feb 1986, Hines 578 ( PRE) . 2017 (Waterburg): Waterburg (–AA), 21 Dec 1970, Rutherford A 12 ( PRE) . 2116 (Okahandja): Thorn tree farm 80 km from Okahandja on road Otjiwarongo (–BD), 6 Mar 1983, Germishuizen 2596 ( PRE) . 2118 (Steinhausen): Hennopsrus farm, on R16 road to Steinhausen (–BB), 5 Mar 1997, Germishuizen 9360 ( PRE) ; Kaokoveld (–BD), Oct 1972, Giess 9781 ( PRE) . 2217 (Windhoek): Windhoek (–CA), 1 Feb 1976, Giess 13927 ( PRE) . 2218 (Omaheke): Omaheke, road D 1793, 21 km N of junction with D1792 (–CB), 22 Apr 1998, Kolberg HK 915 ( PRE) ; Hennopsrus Farm, on R16 road to Steinhausen (–BB), 5 Mar 1997, Germishuizen 9360 ( PRE) . 2219 (Sandfontein): Sandfontein (–CC), 21 Feb 1955, De Winter 2443 ( PRE) ; 5 km from turn off on road to Rietfointein from Buitepos/Gobabis road (–BC), 6 Mar 1997, Germishuizen 9493 ( PRE) .

Botswana. —1824 (Kachikau): 1.75 km South of the Seronga/Savuti track junction near the Sandridge gap (–CC), 21 Jan 1979, Smith 2631 ( PRE) . 2220 (Kalkfontein): 6 km North of Okwa Valley along the track between Ncojane and Mamuno (–AC), 31 May 1905, Skarpe S-448 ( PRE) . 2326 (Kgatleng): Masana Ranch (–CD), 10 Nov 1978, Hansen 3545 ( PRE) . 2324 (Mahalapye): Dinojane to Salajwe road on sand (–DD), 10 Dec 1987, Barnard 409 ( PRE) . 2325 (Lephepe): central Kalahari, Dinojane (–BC), 12 Dec 1986, Barnard 218 ( PRE) . 2426 (Mochudi): Bochudi (–AC), Jan-Apr 1914, Harbor 6585 ( NBG) .

South Africa. — LIMPOPO: 2327 (Ellisras): Njala Nature Reserve (–DA), 5 Feb 1994, Swartz PPS 94–22 ( PRE) . 2329 (Pietersburg) [Polokwane]: Pietersburg [Polokwane ] (–BB), Mar 1919, Breijer 19556 ( PRE) . 2429 (Zebediela): Sunningdale Private Nature Reserve (–AC), 3 Jan 1970, Hofmeyer 158 ( PRE) . — NORTH WEST: 2526 (Zeerust): Zeerust (–CA), Oct 1972, Leendertz 11303 ( PRE) ; Zeerust (–CA), Jan 1928, Thode 1402 ( PRE) . 2527 (Rustenburg): Saulspoort, Kwa-Ramoga in kloof on side of Mountain (–AA), 28 Nov 1977, Germishuizen 00486 (20032) ( PRE) ; Klipvoordam (–BB), 8 Jan 1978, Peters, Gericke and Burelli 3536 ( PRE) . 2529 (Witbank): Stoffberg, next to R555 road (–BD), 14 Jan 2018, Musandiwa 8 ( NBG) . 2624 (Morokweng): ca. 12 km N of Stella, on road to Papiesvlakte (–BD), 3 Mar 1998, Smook 10067 ( PRE) . 2626 (Klerksdorp): Witstinkhoutboom (–AB), 28 Jan 1926, Liebenberg 26 ( PRE) . 2627 (Potchefstroom): Meyer street, near military base (–CA), 9 Dec 2011, Komape, Mabe and Siebert KMS265 ( NBG) . 2724 (Taung): Zoet Vley (–AA), 10 Nov 1988, Speedy 208 ( PRE) ; near Vryburg, Farm Palmyra, 97 km northwest of Vryburg (–CA), 5 Feb 1948, Rodin 3499 ( PRE) ; Andalusia (–DD), 7 Jan 1941, Herre 60661 ( PRE) . 2725 (Bloemhof): Leeuwfontein, 10 km W of Wolmaransstad (–BB), 17 Dec 1974, Van Wyk 742 ( PRE) . — GAUTENG: 2528 (Pretoria): Bultfontein Verena (–BD), 27 Dec 1972, Grobbelaar 1679 ( PRE) ; Christianville, Springbokvlakte road, NW of Montana Secondary School (–CA), 6 Feb 2005, Bester and Archer 5645 ( PRE) ; Arcadia (–CA), Jan 1926, Smith 2089 ( PRE) ; Wonderboom Reserve (–CB), 17 Nov 1944, Wasserfall 3536 ( NBG) ; Verwoerdburg, De Hoeve Farm (–CC), 1 Feb 1776, Victoria 12 ( NU) ; Farm Annoda, 56 km N East of Pretoria (–DA), 20 Oct 2005, Meyer 4542 ( PRE) . — MPUMALANGA: 2431 (Acornhoek): beyond Blyde River Nature Reserve camp (–CA), 21 Jan 1968, Hilliard 6031 ( NU) . 2529 (Witbank): Loskopdam-Donkerhoek (–CA), 11 Feb 1968, Theron 1673 ( PRE) . 2630 (Carolina): Nooitgedach (–CD), 31 Dec 1926, Henrici 1388 ( PRE) . Free State: 2727 (Kroonstad): Klipspruit (–CA), Feb 1928, Pont 294 ( PRE) ; Klipspruit (–CA), Jan 1928, Pont 352 ( PRE) . 2728 (Frankfort): 6 km from Reitz on the road to Rietpan (–CD), 25 Jan 1983, Retief 888 ( PRE) . 2826 (Brandfort): Glen (–CD), Mar 1926, Glen School of Agriculture 3449 ( PRE) . Northern Cape: 2723 (Kuruman): 11.3 km from Kuruman on road to Hotazel (–AD), without date, Brenda 602 ( PRE) . 2824 (Kimberly): Barkly West, Panplaas (near Boetsap ) (–AB), 20 Feb 1974, Hanekom 2233 ( PRE) ; Rooipoort NW corner of Rooipoort farm (–CA), 19 Feb 1991, Phelan 1120 ( PRE) ; Barkley West, Vaalbos National Park (–CB), 23 Feb 1994, Zietsman 2365 ( PRE) .

Figures

FIG. 3. Extrafloral nectaries of Chamaecrista species. A. C. mimosoides, sessile, circular or circular-elliptic. B. C. capensis var. capensis, circular, sub-sessile or attached on small stalk. C. C. biensis, circular, concave, sub-sessile or raised on small stalk. D. C. comosa subsp. capriconia, elliptic, sessile, spreading over the petiole. E. C. comosa subsp. comosa, sessile, slightly sunken in petiole. F. C. grandiglandulata, large, sessile, elliptic, overlapping the sides of petiole. G. C. gordon-grayei subsp. longipedicellata, sub-sessile to sessile, circular. H. C. falcata, extrafloral nectaries, long stalked, concave on top. Vouchers: A. Burtt & Hilliard 3215 (NU). B. Walker 119 (PRE). C. Phelan 1120 (PRE). D. Burger 292 (PRE). E. Arnold 792 (NU). F. Ward 1219 (NH). G. De Winter and Wiss 4423 (PRE). H. Ward 2439 (PRE).Scale bars = 5 mm).

FIG. 5. Known distribution of Chamaecrista biensis in southern Africa.