Wednesday 25 March 2009

Acokanthera oppositifolia


Acokanthera oppositifolia (Lam.) Codd, Bothalia 7: 448 (1961).
APOCYNACEAE
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Rubus said...

Acokanthera G.Don, Gen. Hist. 4: 485 (1838).

Acokanthera laevigata Kupicha, Kew Bull. 37: 58 (1982).
petiole 3-10mm and blade 5·5–12·25 x 3·25–6·7 cm.
Calyx: 2·5–3·5mm
Corolla tube c. 10 mm long
Fruit: 2·5–3·2 x 2–2·5cm.

Acokanthera oblongifolia (Hochst.) Benth. & Hook.f. ex B.D.Jacks., Index Kew. 2: 1262 (1895).
petiole 4–9 mm. long; lamina 6–8·4 x 1·5–4·5 cm.
Corolla tube 14–20 mm. Flowers white tinged pink.
Calyx c. 3 mm. long
Fruit 2–2·5 cm. long, ellipsoid or subglobose

Acokanthera oppositifolia (Lam.) Codd, Bothalia 7: 448 (1961).
petiole 2–6(7) mm. long; lamina 4·6–10·6 x 1·8–6·7 cm.
Calyx 2–3 mm
Corolla tube 9–13·5 mm. long with pink or reddish corolla tube and white lobes
Fruit an ellipsoid berry 12–20 mm. long


Acokanthera rotundata (Codd) Kupicha, Kew Bull. 37: 60 (1982).
petiole 3–7 mm. long, pubescent on upper surface; lamina 3·8–7·5 x 2·5–4·8 cm.
Calyx 2–2·5 mm
Corolla tube 9–12 mm with pink or red corolla tube and white lobes.
Ripe fruit up to 2 cm. in diameter, subglobose,

Acokanthera schimperi (A.DC.) Schweinf., Bol. Soc. Afr. Ital. 10(11-12): 11 (1891).
Leaves petiolate, petiole 3–6 mm long; blade ovate, obovate, elliptic to suborbicular, 1–8(–10) cm long
Sepals ovate, 1–2 mm long
Corolla tube pink or reddish, 8–11 mm long 1.1–6.5 cm wide
Fruit purple when ripe, ellipsoid, 10–25 mm long

between A. oblongifolia and A. oppositifolia
A. oblongifolia having distinctly longer flowers and larger fruits than A. oppositifolia.
The longer petioles and less prominent venation of A. oblongifolia.

so not A. oblongifolia

Monserrate's Acokanthera has:

Leaves: petiole máx: 7mm long; lamina máx: 10,3x3,8cm (biggest leaf I got in my herbarium)
Corolla tubes around 12mm long, bud not much pink or reddish but with white lobes
Fruit 25mm (Only got one, was black-ripe but has probably shrinked a bit from dessecation.)

A. rotundata has smaller leaves
so not A. rotundata

A. oppositifolia has smaller fruits.
so not A. oppositifolia

so I went looking for subtle differences in:

A. schimperi
Shrub or tree 1–10 m high, branching from the base; bark rough grey-brown; slash cream with fine orange streaks; young branches glabrous or pubescent, conspicuously angled and ribbed.
Leaves petiolate, petiole 3–6 mm long; blade ovate, obovate, elliptic to suborbicular, 1–8(–10) cm long, 1.1–6.5 cm wide, rounded or acute at the apex, with a hard mucro, sometimes emarginate, cuneate or rounded at the base, coriaceous, glabrous; secondary veins obscure, especially beneath.
Inflorescence contracted, of many-flowered axillary cymes; sepals ovate, 1–2 mm long, 0.5–1 mm wide, pubescent or glabrous, ciliate.
Corolla tube pink or reddish, 8–11 mm long, glabrous or pubescent on external surface, inner surface pilose in the upper half and wrinkled below; lobes pink outside, white inside, ovate, 2.5–3.5 mm long, 1.5–2.5 mm wide, acuminate at the apex, pubescent at the base inside, glabrous or pubescent outside, ciliate; stamens slightly exserted, inserted at 7–10 mm from the base; anthers ovate, 1–1.5 mm long, acumen 0.2 mm long; pistil 7.5–10 mm long.
Fruit purple when ripe, ellipsoid, 10–25 mm long; seeds up to 13 mm long.

and

A. laevigata
Tree 5–12 m high with white sticky latex; bark pale brown, fissured; slash pale yellow, fibrous, wood white; branches glabrous; branchlets glabrous or puberulous.
Leaves petiolate; petiole 5–6 mm long, glabrous or puberulous; blade elliptic, 4–13 cm long, 3.5–7.3 cm wide, cuneate or rounded at the base, obtuse to rounded or acute at the apex with a hard mucro, rarely emarginate, glabrous to puberulous especially on midrib beneath.
Inflorescence of contracted axillary cymes; sepals ovate, 2.5–3.5 mm long, apiculate, ciliate otherwise glabrous.
Corolla tube pink, 9.5–11 mm long, sparsely pubescent outside, pubescent in the upper half inside; lobes white, ovate-cuspidate, 3–4 mm long, glabrous, densely hairy at the base and mouth of the tube, ciliate; stamens just visible at anthesis; anthers 1 mm long, apiculate at the apex, apiculus 0.6–0.7 mm long; pistil 9–10 mm long.
Fruit ovoid, 2.5–3 cm long, up to 2.5 cm in diameter.

it has the biggest fruit, its ovoid, it doesn't say the color but it gets black not purple, stamens just visible at anthesis
is true but as (maybe) the better way to distinguish is:
sepals ovate, 1–2 mm long -> A. schimperi
sepals ovate, 2.5–3.5 mm long -> A. laevigata

I think its A. schimperi!

20 April 2009 at 12:16
Gerald Luckhurst said...

Rubus,

Thank you for this information. I would expect this plant to be A. oppositifolia. I not sure that A. schimperi is in cultivation. The chief character that you have used to eliminate A. oppositifolia is fruit size yet not all floras agree on a 2cm limit. See here for example:

1. Acokanthera oppositifolia (Lamarck) Codd, Bothalia. 7: 448. 1961.

Cestrum oppositifolium Lamarck, Tabl. Encycl. 2: 5, t. 112, fig. 2. 1794.

Shrubs to 5 m tall. Branchlets compressed when young, terete with age. Petiole 2-6 mm; leaf blade mostly obovate, occasionally elliptic, 4-10 X 2-7 cm, lateral veins 6-10 pairs. Inflorescences sessile or subsessile, clustered, glabrous or puberulent, usually many flowered; bracts brown or distal ones pinkish, ovate. Sepals ovate to very narrowly ovate. Corolla white to pink, tube 0.8-1.3 cm, glabrous or puberulent outside, hairy inside; lobes broadly ovate, 2-4.5 mm. Berry purplish black, globose, 2.5-3 cm in diam. Seeds semiglobose or semi-ellipsoid, 0.8-1.2 cm. 2n = 22.

I will collect a specimen tomorrow for a better look at characteristics of Monserrate plant. The seeds agree with this description. We were extracting them from the berries prior to sowing last week.

Gerald

20 April 2009 at 13:50

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