Chamaecrista, IN, (L.) Moench

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 : 996

TAXONOMIC TREATMENT OF CHAMAECRISTA IN SOUTHERN AFRICA

CHAMAECRISTA (L.) Moench. , Meth. Pl. Bot. Marburg.: 272 (1794); H.S. Irwin & Barneby, Mem. New York Bot. Gard. 35(2): 664 (1982); Brummitt in Fl. Zambesiaca 3(2): 121 (2007).

TYPE species: Chamaecrista nictitans (L.) Moench .

Annual or perennial herbs (in southern Africa), up to 1.8 m high. Stems erect or semi-erect, simple or sub-simple, sometimes with a woody base; branched at or above ground level, glabrous or sub-glabrous, eglandular or rarely glandular (in C. absus ), reddish to purplish on one side (in C. plumosa ), often with short curved and/or long straight, patent greyish or whitish hairs. Leaves paripinnate, 7–150 × 3–25 mm, slightly tapering distally; rachis channelled or crested; stipules straight, or curved, often narrowly triangular; extrafloral nectaries often present on petiole, sometimes between the pairs of leaflets (in C. falcata ), sessile, sub-sessile or raised on distinct stalks, often brown or dark brown. Leaflets in numerous pairs, rarely 2 (in C. absus ), oblong or obovate, linear, rarely falcate (in C. falcata ), base often oblique, apex acuminate or mucronate, midrib sometimes excentric towards the anticous margin, glabrous or subglabrate or with long or short scattered hairs, margins often ciliate. Inflorescence usually axillary or supra-axillary, often 1 to 3 flowered, sometimes up to 8-flowered; bracts and bracteoles resembling stipules; bracteoles 2, above the middle or towards the top of pedicels. Pedicels often 3–30 mm long, rarely up to 45 or 55 mm long in C. capensis and C. falcata , respectively, slightly longer at fruiting, often with short and long patent hairs. Sepals 5, ovate, often with spreading hairs. Petals 5, obovate. Stamens 9 or 10, rarely 5 (in C. absus ). Ovaries densely covered with long or short curved hairs. Pods (15)20–65 × 3–8 mm, flattened, straight or slightly curved, often with appressed hairs. Seeds 2.5–5.0 × 1–3 mm, rhomboid or elliptic, flattened, brown, or light brown to blackish.

KEY TO THE SPECIES OF CHAMAECRISTA IN SOUTHERN AFRICA

1. Leaflets in two pairs; plants glandular; stamens 5....................................................................................... C. absus

1. Leaflets in more than two pairs; plants eglandular; stamens 8 to 10............................................................................. 2

2. Leaf rachis crested, with an upright wing of tissue forming a ridge along the mid-line of the upper surface.....................................3

3. Perennial herbs; stems glabrous to glabrescent or with appressed curved or straight hairs, stems often purplish or reddish on one side ( C. plumosa )..................................................................................................................... 4

4. Prostrate and diffusely branched herbs, multi-stemmed, forming spreading mats to 0.4 m in diameter; glabrous to glabrescent, or with appressed curved greyish hairs; leaves 10–45 mm .......................................................... C. plumosa var. plumosa

4. Erect herbs to 1.8 m tall; often single-stemmed, stems unbranched or few branched in the upper half, glabrous or densely covered with straight greyish or yellow hairs; leaves 15–90 mm ............................................................. C. plumosa var. erecta

3. Annual herbs; stems pubescent with short curved, appressed hairs, stems green or becoming blackish................................... 5

5. Extrafloral nectaries large, 1–2 mm in diameter, overlapping the sides of the petiole................................ C. grandiglandulata

5. Extrafloral nectaries small, 0.2–0.8 mm in diameter, not overlapping the sides of the petiole.........................................6

6. Flowers pale yellow; extrafloral nectaries sessile; widely spread in eastern provinces of South Africa and Swaziland ( Eswatini).................................................................................................. C. mimosoides

6. Flowers bright yellow; extrafloral nectaries sub-sessile (rarely sessile), restricted to Namibia and extends beyond the region to Zimbabwe, absent in South Africa ( C. gordon-grayei ).......................................................................7

7. Pedicels ≤ 10 mm long at flowering, ≤ 15 mm long at fruiting......................... C. gordon-grayei subsp. gordon-grayei

7. Pedicels ≥ 15 mm long at flowering, ≥ 15 mm long at fruiting........................ C. gordon-grayei subsp. longipedicellata

2. Leaf rachis channeled along the upper surface............................................................................................8

8. Extrafloral nectaries present on petiole and between leaflet pairs, raised on distinct stalks 1.0– 1.5 mm long; leaflets falcate........... C. falcata

8. Extrafloral nectaries present on petiole only, sessile, or sub-sessile, or raised on small stalks less than 1 mm long; leaflets linear, oblong, obovate or elliptic............................................................................................................... 9

9. Stipules narrowly falcate............................................................................................ C. falcinella

9. Stipules narrowly triangular.................................................................................................10

10. Annual herbs; flowers pale yellow; pedicels ≤ 10 mm long......................................................... C. stricta

10. Perennial herbs; flowers bright yellow; pedicels ≥ 10 mm long........................................................... 11

11. Extrafloral nectaries circular and concave, short stalked............................................................12

12. Inflorescences 1 or 2 flowered; flowers generally small (to 10 mm long).................................. C. biensis

12. Inflorescences 2 to 4 flowered; flowers generally large (to 17 mm long) ( C. capensis )............................. 13

13. Perennial herbs, to 0.3 m high; multi-stemmed; stems glabrous or covered with short hairs, sometimes with few long scattered greyish hairs.................................................. C. capensis var. capensis

13. Perennial herbs, to 0.6 m high; usually single-stemmed and branching in the upper half; stems with long and short intermixed greyish or yellowish hairs....................................... C. capensis var. flavescens

11. Extrafloral nectaries elliptic, sessile ( C. comosa ).................................................................... 14

14. Extrafloral nectaries sunken in rachis channel; restricted to coastal regions of KwaZulu-Natal and Eastern Cape ................................................................................ C. comosa subsp. comosa .

14. Extrafloral nectaries not sunken in rachis channel, spreading over the petiole; distributed in drier inland areas of northern South Africa (Limpopo, North West, Mpumalanga, and Gauteng) to Swaziland ( Eswatini) and extends beyond the region to Zimbabwe, not occurring in coastal regions...................... .. C. comosa subsp. capriconia