Olinia rochetiana A.Juss.

Extinction risk predictions for the world's flowering plants to support their conservation (2024). Bachman, S.P., Brown, M.J.M., Leão, T.C.C., Lughadha, E.N., Walker, B.E. https://nph.onlinelibrary.wiley.com/doi/full/10.1111/nph.19592

Conservation

Predicted extinction risk: not threatened. Confidence: confident

Oliniaceae, B. Verdcourt. Flora of Tropical East Africa. 1975

Morphology General Habit

Shrub, small tree or less often a large tree, evergreen, usually (1.2–) 4–16 m. tall but occasionally said to reach 27 m.; often a small gnarled bushy tree in exposed rocky places.

Morphology General Bark

Bark grey, smooth or rough, sometimes slightly peeling or flaking, often fissured; blaze white with reddish or purplish border.

Morphology Branches

Branchlets reddish when very young, later pale, mostly squarish, which together with the leaf venation renders sterile twigs easily identifiable.

Morphology Leaves

Leaves opposite or ternate, often bright red when young; blade broadly rounded-elliptic to narrowly elliptic or rounded-rhombic, 0.6–12 cm. long, 0.5–4.5 cm. wide, rounded to acuminate at the apex, the actual apex blunt or emarginate, rounded to cuneate at the base, glabrous or minutely puberulous, paler beneath with the close reticulate venation characteristically darker or pellucid and forming a conspicuous pattern; midrib often reddish, impressed above, prominent beneath; petiole 2–9 mm. long, reddish.

Morphology Reproductive morphology Inflorescences

Inflorescences globose or pyramidal, 1.5–7.5 cm. in diameter, usually many-flowered, the branches often puberulous; pedicels very short or up to about 1 mm. long; bracts very deciduous or rarely persistent, thin, veined, ovate or oblong, cucullate, pubescent, those enveloping a triad of flowers or simple terminal flowers 1.5–6 mm. long, 1–3.5 mm. wide, larger than the secondary bracts enveloping lateral flowers of the triad which measure 1–3.5 mm. long, 1–2 mm. wide.

Morphology Reproductive morphology Flowers

Flowers sweetly scented.

Morphology Reproductive morphology Flowers Calyx

Calyx-tube and combined receptacle ± cylindrical, somewhat narrowed to the base, mostly crimson, glabrous or puberulous, 2.5–7 mm. long, minutely lobed or undulate at the apex.

Morphology Reproductive morphology Flowers Corolla

Petals yellowish cream, white, pink or crimson, often white at first and becoming red later, linear-oblong to distinctly obovate-spathulate, 2.3–5 mm. long, 1–2.5 mm. wide, rounded at the apex, always narrowest towards the base, mostly glabrous but usually pubescent towards the base inside.

Morphology General Scales

Scales crimson-pink, 0.5–1.5 mm. long, 0.5–1.25 mm. wide.

Morphology Reproductive morphology Fruits

Fruit pink or dull crimson, globose or ovoid, 0.5–1 cm. long and wide, usually speckled with pale lenticels, rather woody inside, marked by the circular scar remaining after the calyx-tube has fallen off.

Morphology Reproductive morphology Seeds

Seeds brown, subtrigonous-ovoid, 2.5–3 mm. long and wide, minutely shagreened.

Habitat

Upland dry and moist evergreen forest, forest edges and frequently forming thickets with Rhus etc. in areas where forest has been degraded by fire and other human interference, finally as a relict tree in grassland; 1680–3000 m.

Distribution

K1 K3 K4 K5 K6 T2 T3 T4 T6 T7 U1 U2 U3

Sebola, R.J. & Balkwill, K. 2013. A monographic study of the Oliniaceae. Kew Bulletin 68: 419. https://doi.org/10.1007/s12225-013-9465-x

Morphology Leaves

Primary veins slightly channelled above Secondary veins branch from midrib at 45º – 60º and loop more than once before the margins, slightly conspicuous above, distinctly conspicuous below Leaves broadly elliptic to obovate, slightly discolorous, glabrous on both surfaces, 41 – 65 × 29 – 53 mm base tapering to rounded or slightly cordate apex notched or broadly emarginate margins smooth

Morphology Leaves Petiole

Petiole light green-yellow, glabrous, up to 3 mm long

Morphology Leaves Stipules

Stipules as for the genus

Morphology Reproductive morphology Inflorescences

Inflorescence axillary and terminal, dichasial cyme inflorescence units 12 – 28 mm long, compact or loose peduncle sparsely pubescent, 8 – 24 mm long

Morphology Reproductive morphology Inflorescences Bracts

Bracts caducous, papery and creamy white or leathery and pink, ovate or elliptic, 5 – 8 × 3 – 5 mm, markedly pubescent on both surfaces (for papery ones), glabrous on dorsal surfaces (for leathery ones)

Morphology Reproductive morphology Flowers

Flower 5-merous, subsessile

Morphology Reproductive morphology Flowers Pedicel

Pedicels glaucous, 0.5 – 1.5 mm long

Morphology Reproductive morphology Flowers Hypanthium

Hypanthium broad and thick, glabrous to sparsely pubescent or highly puberulous, throat with hooded scales alternating with petals

Morphology Reproductive morphology Flowers Calyx

Sepals as for the genus

Morphology Reproductive morphology Flowers Corolla

Petals spathulate to slightly oblong, apex slightly apiculate to rounded, base slightly narrow, glabrous on abaxial surfaces, pubescent on margins and the base on adaxial surfaces, cream-white or pink, turning red at maturity, 4 – 10.5 × 2 – 4 mm

Morphology General Scales

Scales puberulent, enclosing stamens, 1 – 2.5 mm long, 0.5 – 1.5 mm wide

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens as for the genus

Morphology Reproductive morphology Flowers Gynoecium Ovary

Ovary 5-locular style glabrous, 2 – 6 mm long stigma capitate or terete

Morphology Reproductive morphology Fruits

Fruit light green when young, pink to red when mature, globose, 6 – 15 mm in diam., glabrous, apex marked by hypanthium scar 4 – 10 mm in diam.

Type

Type: Ethiopia, Choa, near Ankoeber, Rochet 18 (holotype P isotype K!).

Morphology General Habit

Shrubs or medium to large trees up to 15 m high

Morphology General Bark

Bark grey, with peeling scales branchlets light grey

Note

Olinia usambarensis can be distinguished from O. rochetiana s.s. by a 4-merous condition in lateral flowers within an inflorescence unit (vs 5-merous) petal lobes that are broader than long, showy and thick textured (vs narrow, and thinly textured). Olinia rochetiana s.s. is similar to O. usambarensis but can be recognised by coriaceous leaves that are concolorous 5-merous condition in both lateral and terminal flowers (vs 4-merous condition in lateral flowers only) and petal lobes that are spathulate to slightly oblong, narrow and 4 – 11 mm long (vs 2.5 – 5 mm long), with slightly apiculate to rounded apices.

Distribution

Known from Tanzania (Usambara and Kilimanjaro Mts), central to southwestern Kenya, and Uganda around Mt Elgon and environs. Known from north-east and central Ethiopia, south-east of Sudan, Uganda, north-west of Kenya and eastern Tanzania. Map 10.