Monanthotaxis suffruticosa P.H.Hoekstra, 2021

Hoekstra, P. H., Wieringa, J. J., Maas, P. J. M. & Chatrou, L. W., 2021, Revision of the African species of Monanthotaxis (Annonaceae), Blumea 66 (2), pp. 107-221 : 202-203

69. Monanthotaxis suffruticosa P.H.Hoekstra , sp. nov. — Plate 5h; Map 43

Monanthotaxis suffruticosa is the only species of Monanthotaxis which grows as a subshrub just up to 40 cm high. It closely resembles M. faulknerae and M. trichocarpa as all 3 species have c. 24 stamens in two whorls, monocarps covered with erect hairs, and leaves punctate in sicco. Besides the growth form, M. suffruticosa differs from M. trichocarpa in the oblong-elliptic leaves, which are generally obovate in M. trichocarpa ; from M. faulknerae it differs by generally broader leaves (2.1–3.8 cm vs 0.7–2.6 cm) and more carpels per flower (14–16 vs 8–10). — Type: K. B. Vollesen MRC3362 (holo WAG0053977 ; iso C, EA, K, UPS), Tanzania, Lindi, Selous Game Reserve , Madaba, 300 m, 7 Mar. 1976. Paratypes : E. M. C. Groenendijk et al. 1029 ( LMU not seen, MO), Mozambique, Nampula, distrito de Monapo, reserva florestal do Sr.Wolf em Monapo, 10 Feb.1984 ; M. C. LÖtter & Turpin 1741 ( K), Mozambique, Cabo Delgado, Pr 1040, 25 km west of Palma , 132 m, 22 Mar. 2009 ; T. Rees 155 ( C, EA), Tanzania, Lindi, Selous game reserve, Mkangira área , 300 m, 8 July 1971 ; K. B. Vollesen MRC2714 ( C, EA), Tanzania, Lindi, Selous game reserve, c. 18 km SW of Kingupira, 175 m, 10 Sept. 1975 .

Etymology. This species is named suffruticosa as it is the only species of Monanthotaxis which grows as a subshrub (Latin: suffrutex).

Subshrub, branching from the base, to 40 cm tall; young branches orange to reddish brown, glandular-punctate, densely covered with erect, yellowish hairs 0.4–0.8 mm long; old branches reddish brown, sparsely covered with hairs. Leaves: petiole 2–3.5 mm long, 0.6–1 mm diam, terete, indument as on branches; lamina oblong-elliptic to narrowly oblong-elliptic, 4–7.4 by 2.1–3.8 cm, 1.5–3 times longer than wide, subcoriaceous, punctate, discolorous, glossy dark green above, dull greenish white below, young leaves above sparsely covered with erect, white hairs to 1 mm long, becoming glabrous, primary vein more densely covered with erect, white hairs, below sparsely covered with ascending to erect, white hairs 0.3–0.5 mm long, more densely so on primary vein, base rounded to slightly subcordate, glands hardly visible, apex rounded to obtuse, secondary veins 5–9 per side, from base curving upwards, tertiary venation percurrent, slightly reticulate above. Inflorescences extra-axillary, composed of solitary flowers; sympodial rachis absent; pedicels 11–16 mm long, 0.2–0.4 mm diam, fruiting pedicels 0.5–0.7 mm diam, sparsely covered with erect hairs 0.3–0.4 mm long; lower bract absent; upper bract in the upper half of the pedicel or sometimes absent, ovate, 1.3–1.8 by 0.7–1 mm, indument as on pedicel; flower buds globose. Flowers bisexual; sepals free, depressed ovate to orbicular, 2.5–3.5 by 3.2–3.4 mm, apex rounded, densely covered with erect, short hairs, persistent in fruit, slightly accrescent; receptacle c. 2.5 mm diam, slightly convex; petals colour in vivo unknown, 6, in two whorls, outer petals ovate to elliptic, 10.5–12.5 by 5.2–7.8 mm, outside sparsely covered with ascending, yellowish hairs 0.2–0.3 mm long, inside covered with very short hairs near the apex and margins, inner petals ovate, 8.2–9 by 4.1–4.6 mm, outside and apex and margins of the inside covered with yellowish, short hairs; stamens 23 or 24, in two whorls, free, linear-obovoid, 1.3–1.5 mm long, filaments 0.4–0.5 mm long, thecae latrorse to extrorse, connective truncate, prolonged outward, not hiding the thecae, glabrous, staminodes absent; carpels 14–16, subcylindric, c. 1.9 by 0.3 mm, densely hairy, ovules 3, lateral, stigma elongate, c. 0.9 mm long, glabrous. Monocarps up to 4, yellow, ellipsoid, 14–23 by 4.8–5.5 mm, constricted between the seeds, slightly verrucose, covered with erect, yellowish hairs, apex apiculate, stipes 2.5–4 mm long. Seeds 1–3, ellipsoid, c. 8.5 by 4.4 mm, ochre-brown, apex flattened, raphe slightly visible as a longitudinal furrow from base to apex.

Distribution — Tanzania (Lindi), Mozambique (Cabo Delgado, Nampula).

Habitat & Ecology — In woodland and dry coastal forest, on sandy soil. Altitude: 132– 300 m. Flowering: February, March; fruiting: March, July, September.

Preliminary IUCN conservation status — Endangered (EN): B2ab(iii). EOO: 88 043 km 2, AOO: 20 km 2. This species is known from 5 collections in 4 locations of which 2 are nature reserves. However, the Selous Game Reserve was placed in 2014 on the UNESCO list of world heritage in danger and the other areas are under threat of habitat destruction and degradation.

Figures

Map 43 Distribution of Monanthotaxis suffruticosa P.H.Hoekstra (■) and M. trichanta (Diels) Verdc. (●).