Chamaecrista gordon-grayei Musandiwa & Boatwr., 2022

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 : 1003-1005

7. Chamaecrista gordon-grayei Musandiwa & Boatwr. , sp. nov.

TYPE: NAMIBIA. Andara (1821), Caprivi-Zipfel, Popa f ä alle [Popa Falls] Caprivi Zipfel [Caprivi Strip] (– BA), 9 Mar 1958, Giess 2020 (holotype: WIND!).

Annual herbs to 1.5 m high. Stems erect or semi-erect, with curved hairs. Leaves paripinnate, 36–104 × 2–4 mm, slightly tapering distally; stipules 6–11 mm long, triangular, base oblique, apex acuminate; extrafloral nectaries, sessile or raised on small stalk, ± 0.5 × 0.2–0.4 mm circular; rachis crested. Leaflets 20–65-jugate, 15–90 × 0.2–0.3 base oblique, apex acuminate, tapering distally; margin glabrous to ciliate. Inflorescence supra-axillary, 1–2 flowered; flowers 4–5 × 4–6; bract glabrous, base oblique, apex acuminate; bracteoles 2, glabrous, towards top of pedicels. Pedicels with short hairs, at flowering 7–25 mm long, at fruiting 10–30 mm long. Sepals 5, narrowly lanceolate, 6–9 × 1–4 mm, with or without appressed hairs, on the outer surface. Petals 5, ovate, ± 6 × 2–6 mm; bright yellow. Stamens 9–10, slightly curved, anthers in three series, 2(3) small, 2–3 mm long, 4 middle, ± 4 mm long, 3(4) large, ± 5 mm long, with very short filament 1–2 mm long. Ovary ± 0.5 mm long, densely covered with greyish to whitish hairs, style glabrous, curved. Pods (30) 50–63 mm long, straight, or slightly curved with suppressed hairs. Seeds not seen. Figure 10 .

Diagnostic Characters — Chamaecrista gordon-grayei shares the crested leaf rachis with C. grandiglandulata and C. mimosoides , but is distinguished from those species by the long leaves (36–104 mm long), with sub-sessile to sessile, circular extrafloral nectaries (large extrafloral nectaries that overlap the sides of petiole in C. grandiglandulata and small, circular or circular-elliptic extrafloral nectaries in C. mimosoides ), and bright yellow flowers.

Etymology — Chamaecrista gordon-grayei is named in honour of Dr. Kathleen D. Gordon-Gray (1918–2012) who showed remarkable passion for the southern African flora.

Two subspecies are recognised:

Figures

FIG. 10. Morphology of Chamaecrista gordon-grayei. A1–A5. Petals. B. Ovary, densely hairy. C1–C3. Stamens, with anthers in three series. Voucher: Muller & Giess 554 (WIND). Scale bars = 1 mm.