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16: Stimulants

Coffea congensis Froehner

RUBIACEAE

Coffea congensis is native to Central Africa along the Congo, Oubangui and Sangha rivers in the northern Democratic Republic of Congo (Zaire), the southern Republic of Central Africa, Congo (Brazzaville) and south-eastern Cameroon. It is generally not planted for coffee production, but is often kept in germplasm collections, for example in Java and the Philippines.

The comparatively small seeds (generally referred to as coffee beans) are rarely used to prepare coffee. Coffea congensis is of importance however in interspecific breeding programmes, especially to introgress improved quality into Coffea canephora.

An evergreen shrub, up to 7 m tall, with richly branched stem. Leaves opposite; stipules interpetiolate, green, triangular to semi-orbicular; petiole 2.5—14 mm long; blade narrowly elliptical to lanceolate or oblanceolate, 4.5—18(—25) cm x 1.2—6.5(—9.5) cm, base cuneate, margin entire, apex acuminate, with hairy domatia below. Inflorescence axillary, composed of 1—3(—5) cymes with comparatively long peduncles, each axil with 1—17 flowers; flowers (4—)5—6(—7)-merous; receptacle urn-shaped to campanulate, often puberulous; calyx minute, truncate or lobed or rarely minutely toothed; corolla white, tube cylindrical, (2—)6—10(—11) mm long, lobes oblong to ovate-oblong, (6—)8—12(—15) mm long; disk annular, slightly lobed; filaments attached to the lower half of the anther; ovary inferior, 2-locular with a single ovule per cell, style (5—)8—15(—22) mm long, with 2 stigmas. Fruit a drupe, 1—6 per axil, ellipsoid or rarely ovoid or subglobose, 9—17 mm x 5—10 mm, red. Seed ellipsoid, about 12 mm long. Coffea congensis is a lowland coffee that grows in wet primary forest and tolerates waterlogging. It readily hybridises with Coffea canephora Pierre ex Froehner to form the well-known 'Congusta' of Java and the CxR cultivar of India. It is sometimes suggested that Coffea congensis is merely a form of Coffea canephora.

[17] Chevalier, A., 1947. Les caféiers du globe [The coffees of the world]. Fasc. 3. Encyclopédie Biologique 28. Paul Lechevalier, Paris, France. 356 pp.
[30] Heyne, K., 1927. De nuttige planten van Nederlandsch-Indië [The useful plants of the Dutch East Indies]. 2nd edition, 3 volumes. Departement van Landbouw, Nijverheid en Handel in Nederlandsch-Indië. 1953 pp. (3rd edition, 1950. van Hoeve, 's-Gravenhage/Bandung, the Netherlands/Indonesia. 1660 pp.).
[41] Lebrun, J., 1941. Recherches morphologiques et systématiques sur les caféiers du Congo [Morphological and systematic studies on the coffees of Congo]. Mémoires de l'Institut Royal Colonial Belge, Section des Sciences Naturelles et Médicales 11(3): 1—180.
[43] Mansfeld, R., 1986. Verzeichnis landwirtschaftlicher und gärtnerischer Kulturpflanzen (ohne Zierpflanzen) [Register of agricultural and horticultural plants (without ornamentals)]. 2nd edition, revised by J. Schultze-Motel. 4 volumes. Springer Verlag, Berlin, Germany. 1998 pp.
[63] Stoffelen, P., Robbrecht, E. & Smets, E., 1996. The 'arabica-congensis complex': five Coffea-species with a problematic delimitation. In: Robbrecht, E., Puff, C. & Smets, E. (Editors): Second International Rubiaceae Conference, Proceedings. Opera Botanica Belgica 7. National Botanic Garden of Belgium, Meise, Belgium. pp. 237—248.
[73] Wellman, F.L., 1961. Coffee; botany, cultivation and utilization. Leonard Hill, London, United Kingdom & Interscience Publishers, New York, United States. 488 pp.
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M.S.M. Sosef

Sosef, M.S.M., 2000. Coffea congensis Froehner. In: van der Vossen, H.A.M. and Wessel, M. (Editors): Plant Resources of South-East Asia No 16: Stimulants. PROSEA Foundation, Bogor, Indonesia. Database record: prota4u.org/prosea