Coffea congensis (PROSEA)

Plant Resources of South-East Asia
Introduction

Family: Rubiaceae

Distribution

C. 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.

Uses

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

Observations

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 × 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 × 5-10 mm, red. Seed ellipsoid, about 12 mm long. C. congensis is a lowland coffee that grows in wet primary forest and tolerates waterlogging. It readily hybridises with C. canephora Pierre ex Froehner to form the well-known "Congusta" of Java and the C×R cultivar of India. It is sometimes suggested that C. congensis is merely a form of C. canephora .

Selected sources

17, 30, 41, 43, 63, 73, 76.

Authors

M.S.M. Sosef