Coffea L.

Rubiaceae, B. Verdcourt. Flora of Tropical East Africa. 1976

Morphology General Habit

Shrubs or small trees

Morphology Leaves

Leaves opposite, petiolate, glabrous; domatia usually present, the cavity completely or partially defined, glabrous or pubescent; stipules very shortly united above the axils, obtuse to aristate, usually with colleters within

Morphology Reproductive morphology Flowers

Flowers hermaphrodite, (4–)5–8(–12)-merous, borne with leaves or precociously, 1–many per axil or rarely terminal on spurs; inflorescence-stalks (including pedicel) individual or grouped on common peduncle, glabrous or pubescent (but this character is often obscured by resinous exudate); bracteoles 1–4, usually cupular, stipule-like with rudimentary lobes or sometimes bearing 2 linear or subfoliaceous lobes; occasionally additional free, scale-like bracteoles are borne towards apex of inflorescence-stalks

Morphology Reproductive morphology Flowers Calyx

Calyx-tube campanulate to turbinate; limb usually ± obsolete and shorter than the disc, occasionally equalling or rarely exceeding the disc, truncate to dentate, usually beset with colleters

Morphology Reproductive morphology Flowers Corolla

Corolla white or occasionally pink, glabrous; tube cylindrical and widened at throat or somewhat funnel-shaped, shorter than, subequal to or, occasionally, a little longer than the lobes; lobes contorted in bud, spreading

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens attached at mouth of corolla-tube, exserted, erect; filaments ± 1/3 the length of the anther; anthers linear, attached dorsally up to 1/3 from the base

Morphology Reproductive morphology Flowers Disc

Disc annular

Morphology Reproductive morphology Flowers Gynoecium Pistil

Ovary 2-locular; ovules solitary, subpeltately attached to the middle of the septum; style slender, glabrous, exceeding the corolla-tube; stigma exserted, with 2 usually divergent arms

Morphology Reproductive morphology Fruits

Fruit a ± ellipsoidal drupe, usually fleshy, containing (1–)2, ± coriaceous, 1-seeded pyrenes

Morphology Reproductive morphology Seeds

Seed oblong-ellipsoid, grooved on inner face; testa thin with compressed cellular sculpturing that superficially appears striated, shiny (referred to as silver-skin by coffee growers); endosperm pale in colour, horny, asymmetrically folded from the groove; embryo erect, somewhat curved.

Timothy M. A. Utteridge and Laura V. S. Jennings (2022). Trees of New Guinea. Kew Publishing. Royal Botanic Gardens, Kew

Distribution

A genus of c. 126 species occurring naturally in tropical and southern Africa, through the western Indian Ocean and tropical Asia to Queensland in Australia. Three species occur in New Guinea, two natives: Coffea brassii (J.-F.Leroy) A.P.Davis and C. mabesae (Elmer) J.-F.Leroy); and the widely cultivated Ethiopian native, C. arabica L., which is known to be naturalised. The latter is the only taxon in the area likely to reach 5 m in height, the others rarely exceeding 3 m.

Morphology General Habit

Trees, treelets or shrubs to 10 m; wood hard, branches often ±horizontal-Raphides absent

Morphology Leaves Stipules

Stipules triangular, apex obtuse to apiculate, sometimes coated with a resinous layer

Morphology Leaves

Leaves usually with domatia in axils of midrib and secondary veins

Morphology Reproductive morphology Inflorescences

Inflorescences condensed sessile cymes, axillary or axillary then terminal, paired either side of stem, axes sometimes coated with a resinous layer; bract-, ±foliaceous- or stipule-like calyculi usually present

Morphology Reproductive morphology Flowers

Flowers bisexual; calyx tube short, truncate or with small lobes; corolla white (rarely light pink), narrowly funnel-shaped, 5(–8)-merous, lobes contorted to the left in bud; anthers exserted (rarely included); disk present, often well developed; ovary 2-locular, placentation axile, ovules 1 per locule, style exserted (rarely included), stigma bifid

Morphology Reproductive morphology Fruits

Fruit a 2-seeded berry (rarely 1 by abortion), green ripening through yellow to red; seeds ‘coffee beans’ with a longitudinal groove along the flat surface

Ecology

Native Coffea species are found at low elevations along watercourses, in monsoon forest and scrublands and on stabalised dunes. Coffea arabica may be found naturalised at low to mid elevations, particularly near sites of former cultivation.

Recognition

The genus may be confused with genera in the tribe Vanguerieae, but Coffea can be recognised through the sessile, paired inflorescences with calyculi, showy white flowers, bifid stigmas, a well developed disk which often exceeds the truncate calyx in fruit, and the distinctive ’coffee-bean’ type seeds. Shiny resin may be seen on stipules and on inflorescences, especially when dried.

Rubiaceae, D.M.Bridson & B.Verdcourt. Flora Zambesiaca 5:3. 2003

Morphology Reproductive morphology Flowers Disc

Disk annular.

Morphology Reproductive morphology Flowers Gynoecium Pistil

Ovary 2-locular; ovules solitary, subpeltately attached to the middle of the septum; style slender, glabrous, exceeding the corolla tube; stigma exserted with 2 usually divergent arms*.

Morphology Reproductive morphology Fruits

Fruit a ± ellipsoidal drupe, usually containing (1)2 ± coriaceous, 1-seeded pyrenes.

Morphology Reproductive morphology Seeds

Seed oblong-ellipsoid, grooved on inner face; testa thin with compressed cellular sculpturing that superficially appears striated, shiny (referred to as “silver- skin” by coffee growers); endosperm pale in colour, horny, asymmetrically folded from the groove; embryo erect, somewhat curved.

Morphology General Habit

Shrubs or small trees.

Morphology Leaves

Leaves opposite, petiolate, glabrous; domatia usually present, the cavity completely or partially defined, glabrous or pubescent; stipules very shortly united above the axils, obtuse or aristate, usually with colleters within.

Morphology Reproductive morphology Flowers

Flowers hermaphrodite, (4)5–8(12)-merous, borne with leaves or precociously (or terminal on spurs, in subgen. Baracoffea, not in the Flora Zambesiaca area); inflorescence units 1 or 2–4 per leaf axil; inflorescence stalks (including pedicel) individual or grouped on a common peduncle, glabrous or pubescent (but this character is often obscured by sticky exudate); cupular bracts/bracteoles (cupules*) in a series of 1–3(4), each with 2 stipule-derived (stipular lobes) and 2 leaf- derived (foliar lobes) (TAB. 92/B6) and with colleters within; stipular lobes usually stipule-like; foliar lobes rudimentary, linear or subfoliaceous; occasionally a bracteolar cupule present at base of pedicel, variously divided sometimes ± to the base; scale-like bractlets borne along true pedicel up to base of calyx tube or absent, often with colleters partly protruding.

Morphology Reproductive morphology Flowers Calyx

Calyx tube campanulate to turbinate; limb usually ± obsolete and shorter than the disk, occasionally equalling or rarely exceeding the disk, truncate to dentate, usually beset with colleters.

Morphology Reproductive morphology Flowers Corolla

Corolla white or occasionally pink, glabrous; tube cylindrical and widened at throat or somewhat funnel-shaped, shorter than, subequal to or, occasionally a little longer than the lobes; lobes contorted in to the left bud, spreading.

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens attached at mouth of corolla tube, exserted, semi-erect to divergent; filaments ± one-third the length of the anther; anthers linear, attached dorsally up to one-third from the base.

Rubiaceae, B. Verdcourt. Flora of Tropical East Africa. 1976

Morphology General Habit

Shrubs or small trees

Morphology Leaves

Leaves opposite, petiolate, papery to subcoriaceous; domatia usually present, hairy; stipules shortly sheathing, with a truncate to triangular limb usually bearing a linear to subulate lobe, often caducous

Morphology Reproductive morphology Flowers

Flowers appearing precociously or not, hermaphrodite, (4–)5-merous, terminal, less often axillary or both terminal and axillary, sessile to shortly pedicellate; bracts and bracteoles absent or glumaceous, flower sometimes subtended by young leaves above the bracteoles

Morphology Reproductive morphology Flowers Calyx

Calyx-tube ovate to campanulate; limb subequalling the disc, 5-lobed or irregularly toothed, and margin beset with colleters

Morphology Reproductive morphology Flowers Corolla

Corolla white; tube cylindrical but widened at apex, equalling to over twice as long as the lobes, glabrous or sparsely pubescent outside; lobes contorted in bud, spreading

Morphology Reproductive morphology Flowers Androecium Stamens Anthers

Anthers set at mouth of corolla, sessile, linear, shortly apiculate at apex, scarcely hastate at base, usually attached above to well above the mid-point, with the apical part exserted or sometimes entirely included, occasionally tending to adhere towards base

Morphology Reproductive morphology Flowers Disc

Disc annular

Morphology Reproductive morphology Flowers Gynoecium Pistil

Ovary 2-locular; placentas small, attached to middle or somewhat above middle of septum; style cylindrical, slender, glabrous, usually short, reaching less than 1/3 of the way up the corolla-tube; stigma included, bifid; arms linear to narrowly oblong or ?lanceolate, sometimes not separating

Morphology Reproductive morphology Fruits

Fruit a drupe, ellipsoid or broader than long and distinctly 2-lobed, containing 2, 1-seeded cartilaginous pyrenes; calyx-lobes greatly or not at all accrescent

Morphology Reproductive morphology Seeds

Seed oblong-ellipsoid, grooved on inner face; endosperm pale in colour, horny, asymmetrically folded from groove, embryo somewhat curved; testa thin, smooth at low magnifications.