Rubiaceae Juss.

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

Morphology General Habit

Small to large trees, shrubs (including suffrutices from woody rootstocks) or less often annual or perennial herbs or woody or herbaceous climbers, sometimes spiny; raphides (tab. 1/7) present or absent; crystal sand absent or present (these two mutually exclusive) Small to large trees, shrubs (including suffrutices from woody rootstocks) or less often annual or perennial herbs or woody or herbaceous climbers, sometimes spiny; raphides (tab. 1/7) present or absent; crystal sand absent or present (these two mutually exclusive) Small to large trees, shrubs or less often annual or perennial herbs or woody or herbaceous climbers, sometimes spiny; tissues in many tribes containing abundant rhaphides

Morphology Leaves

Leaves opposite or occasionally verticillate, decussate, almost always entire, very rarely sparsely toothed or lobed (not in the Flora Zambesiaca area), always obviously stipulate (save in some Rubieae, where the stipules may be considered leaf-like or almost absent according to interpretation); domatia (mite associated pits or tufts of hairs) very often present axils of lateral nerves on the leaf lower surface; bacterial nodules present in a few genera Leaves opposite or occasionally verticillate, decussate, almost always entire, very rarely sparsely toothed or lobed (not in the Flora Zambesiaca area), always obviously stipulate (save in some Rubieae, where the stipules may be considered leaf-like or almost absent according to interpretation); domatia (mite associated pits or tufts of hairs) very often present axils of lateral nerves on the leaf lower surface; bacterial nodules present in a few genera Leaves opposite or verticillate, decussate, almost always entire, very rarely (not in Africa) palmatifid, toothed or finely denticulate, always obviously stipulate (save in some Rubieae, where the stipules may be considered foliar or almost absent according to interpretation), the stipules interpetiolar or intrapetiolar, entire or, particularly in herbaceous genera, variously divided into lobes or fimbriae, often tipped or separated by mucilaginous hairs known as colleters and often with colleters inside the base; the leaves in certain tribes sometimes contain small bacterial nodules

Morphology Leaves Stipules

Stipules interpetiolar or occasionally intrapetiolar (mostly New World taxa); lobes shortly fused above the petioles and sometimes forming a sheath, or lobes free, entire, bifid or rarely laciniate, or particularly in herbaceous genera, fimbriate, often tipped with or separated by colleters (mucilaginous glands) (tab. 74), often with colleters inside the limb, especially towards the base Stipules interpetiolar or occasionally intrapetiolar (mostly New World taxa); lobes shortly fused above the petioles and sometimes forming a sheath, or lobes free, entire, bifid or rarely laciniate, or particularly in herbaceous genera, fimbriate, often tipped with or separated by colleters (mucilaginous glands) (tab. 74), often with colleters inside the limb, especially towards the base

Morphology Reproductive morphology Inflorescences

Inflorescences terminal or axillary, basically thyrsoid, variously aggregated into panicles etc., occasionally in globose heads sometimes to an extent that the ovaries are adnate, or sometimes flowers solitary; bracts vestigial to well developed, even conspicuous Inflorescences terminal or axillary, basically thyrsoid, variously aggregated into panicles etc., occasionally in globose heads sometimes to an extent that the ovaries are adnate, or sometimes flowers solitary; bracts vestigial to well developed, even conspicuous

Morphology Reproductive morphology Flowers

Flowers regular or slightly to distinctly (not in Africa) zygomorphic, hermaphrodite or less often unisexual, homostylous, in which case very often protandrous, with or without pollen presentation (tab. 73/F,G), or rarely protogynous (not in Africa), or heterostylous with 2 or less often 3 forms (long-styled (dolichostylous), short-styled (brachystylous) or equal-styled (isostylous) (tab. 73/E) Flowers rarely solitary, mostly in various terminal or axillary inflorescences, all basically cymose but variously aggregated into panicles, etc., occasionally in globose heads to an extent that the ovaries are adnate; bracts vestigial to well developed, even conspicuous; flowers usually hermaphrodite, rarely unisexual, regular or nearly so (except in Posoqueria (America)) or corolla tube rarely curved, homostylous or quite often heterostylous with 2 or rarely 3 forms (long-styled (dolichostylous), short-styled (brachystylous) or equal-styled (isostylous)) Flowers regular or slightly to distinctly (not in Africa) zygomorphic, hermaphrodite or less often unisexual, homostylous, in which case very often protandrous, with or without pollen presentation (tab. 73/F,G), or rarely protogynous (not in Africa), or heterostylous with 2 or less often 3 forms (long-styled (dolichostylous), short-styled (brachystylous) or equal-styled (isostylous) (tab. 73/E)

Morphology Reproductive morphology Flowers Calyx

Calyx gamosepalous, the tube (i.e. calyx tube**) mostly adnate to the ovary, the limb with tubular part (i.e. limb-tube) present or absent, truncate or bearing minute teeth to well developed lobes (tab. 73/A1–A4), valvate (often separated by sinuses), or less often imbricate or contorted in aestivation, in a few genera 1–several lobes sometimes slightly to considerably enlarged to form a leaf-like often coloured blade (calycophyll) (tab. 73/A5) Calyx gamosepalous, the tube (i.e. calyx tube**) mostly adnate to the ovary, the limb with tubular part (i.e. limb-tube) present or absent, truncate or bearing minute teeth to well developed lobes (tab. 73/A1–A4), valvate (often separated by sinuses), or less often imbricate or contorted in aestivation, in a few genera 1–several lobes sometimes slightly to considerably enlarged to form a leaf-like often coloured blade (calycophyll) (tab. 73/A5) Calyx gamosepalous, the tube mostly adnate to the ovary, (3)4–5(8)-toothed or lobed, sometimes only minutely so, with open, valvate, imbricate or contorted aestivation, 1 or several lobes sometimes slightly to very considerably enlarged to form a leafy often coloured lamina

Morphology Reproductive morphology Flowers Corolla

Corolla predominantly white but sometimes coloured, small to large and showy, gamopetalous, mostly salver- shaped to funnel-shaped or less often campanulate, occasionally tube very short, the tube rarely curved, (3)4–5(11)-lobed, the lobes contorted (mostly to the left, infrequently to the right) or valvate (sometimes induplicate or reduplicate), with or without a contact zone (i.e. thickened margin), less often imbricate (tab. 73/B–D) Corolla predominantly white but sometimes coloured, small to large and showy, gamopetalous, mostly salver- shaped to funnel-shaped or less often campanulate, occasionally tube very short, the tube rarely curved, (3)4–5(11)-lobed, the lobes contorted (mostly to the left, infrequently to the right) or valvate (sometimes induplicate or reduplicate), with or without a contact zone (i.e. thickened margin), less often imbricate (tab. 73/B–D) Corolla small to large and showy, gamopetalous, rotate to salver-shaped or funnel-shaped, the tube often very long, (3)4–5(11)-lobed, the lobes mostly contorted or valvate, sometimes valvate-induplicate, rarely imbricate or quincuncial

Morphology Reproductive morphology Flowers Androecium

Stamens usually as many as the corolla lobes and alternate with them, epipetalous or not (some New World tribes only); anthers basi- or more often dorsifixed, introrse rarely porate (not in the Flora Zambesiaca area), the thecae rarely transversely multilocellate Pollen various, mostly simple, isopolar and 3- colporate, but sometimes porate, the number of colpi or pores varying from 2 to 25, globose, ovoid or discoid, sometimes (in some Gardenieae) in tetrads or rarely in polyads Stamens usually as many as the corolla-lobes and alternate with them, epipetalous; anthers basi-or dorsifixed, introrse, the thecae rarely multilocellate transversely Pollen various, mostly simple, isopolar and 3-colporate, but sometimes porate, the number of colpi or pores varying from 2–25, globose, ovoid or discoid, sometimes (in some Gardenieae) in tetrads or rarely polyads Pollen various, mostly simple, isopolar and 3- colporate, but sometimes porate, the number of colpi or pores varying from 2 to 25, globose, ovoid or discoid, sometimes (in some Gardenieae) in tetrads or rarely in polyads Stamens usually as many as the corolla lobes and alternate with them, epipetalous or not (some New World tribes only); anthers basi- or more often dorsifixed, introrse rarely porate (not in the Flora Zambesiaca area), the thecae rarely transversely multilocellate

Morphology Reproductive morphology Flowers Nectaries

Disk usually functioning as a nectary, positioned above the ovary inside the base of the calyx limb, annular to cushion-shaped or tubular, sometimes 2-lobed, occasionally fused to base of calyx limb-tube (Naucleeae) or absent (in wind-pollinated flowers) Disc often present, 2-lobed or tubular Disk usually functioning as a nectary, positioned above the ovary inside the base of the calyx limb, annular to cushion-shaped or tubular, sometimes 2-lobed, occasionally fused to base of calyx limb-tube (Naucleeae) or absent (in wind-pollinated flowers)

Morphology Reproductive morphology Flowers Gynoecium

Ovary inferior, rarely half-inferior or superior (in Gaertnera), syncarpous of 2–10(12 or more) carpels, but predominantly of 2, and therefore predominantly 2-locular, but 3–10(12) (in Urophylleae can appear higher than actual carpel number due to supplementary incomplete partitions), or infrequently uni-locular (or partly so); ovules l–numerous per locule; placentation axile (attached to septum at apex, middle or base, usually on a placenta, often embedded in fleshy placentas) or infrequently (in some Gardenieae) parietal; ovules anatropous; style simple, usually long (but very short in Rubieae) and narrow, at the top either cylindrical, clavate, or otherwise modified to form a pollen presenter (the actual stigmatic surface sometimes confined to specific areas, eg the inner faces of the lobes**), or divided into 2–many (according to number of carpels) linear, spathulate or clavate stigmatic lobes Ovary inferior, rarely half-inferior or (in Gaertnera) superior, syncarpous of 2–5 or more carpels, but predominantly of 2 and therefore predominantly 2-locular, but 3–5 or even 12 or more (eg in Urophylleae due to supplementary incomplete partitions); placentation axile or (in some Gardenieae) parietal; ovules 1-many per locule, often embedded in fleshy placentas, erect, basal or horizontal, anatropous; style simple, usually long and narrow, the “stigma” either cylindrical, clavate, or otherwise modified to form a “receptaculum pollinis” or divided into 2-many linear, spathulate or clavate lobes, the actual stigmatic surface sometimes confined to certain areas, eg the inner faces of the lobes Ovary inferior, rarely half-inferior or superior (in Gaertnera), syncarpous of 2–10(12 or more) carpels, but predominantly of 2, and therefore predominantly 2-locular, but 3–10(12) (in Urophylleae can appear higher than actual carpel number due to supplementary incomplete partitions), or infrequently uni-locular (or partly so); ovules l–numerous per locule; placentation axile (attached to septum at apex, middle or base, usually on a placenta, often embedded in fleshy placentas) or infrequently (in some Gardenieae) parietal; ovules anatropous; style simple, usually long (but very short in Rubieae) and narrow, at the top either cylindrical, clavate, or otherwise modified to form a pollen presenter (the actual stigmatic surface sometimes confined to specific areas, eg the inner faces of the lobes**), or divided into 2–many (according to number of carpels) linear, spathulate or clavate stigmatic lobes

Morphology Reproductive morphology Fruits

Fruit small to very large, 2–many-seeded, dehiscent (capsules either loculicidal, septicidal, opening by a beak or infrequently circumscissile, or splitting into mericarps), or indehiscent (berries, including forms with woody walls, or drupes), occasionally (eg in Nauclea and Morinda) united to form syncarps; if drupes containing one-seeded pyrenes thin- or thick-walled, opening by pre-formed germination slits or not, or less often a multi-seeded stone Fruit small to very large, 2–many-seeded, dehiscent (capsules either loculicidal, septicidal, opening by a beak or infrequently circumscissile, or splitting into mericarps), or indehiscent (berries, including forms with woody walls, or drupes), occasionally (eg in Nauclea and Morinda) united to form syncarps; if drupes containing one-seeded pyrenes thin- or thick-walled, opening by pre-formed germination slits or not, or less often a multi-seeded stone Fruit small to quite large (0|2–20 cm.), a capsule, berry or drupe or indehiscent or woody, occasionally (eg in Naulea and Morinda) united to form syncarps, (1)2-many-seeded, if capsules then loculicidal or septicidal or opening by a beak

Morphology Reproductive morphology Seeds

Seeds small to rather large, sometimes winged; testa cells in some tribes with very distinct pits; endosperm present (save in Guettardeae), entire or ruminate; embryo straight or rarely curved; radicle erect or horizontal, mostly longer than the cotyledons, orientation pendulous Seeds small to rather large, sometimes winged; testa cells in some tribes with very distinct pits; endosperm present (save in Guettardeae), entire or ruminate; embryo straight or rarely curved; radicle erect or horizontal, mostly longer than the cotyledons, orientation pendulous Seeds small to rather large, sometimes winged; testa cells in some tribes with very distinct pits; albumen present (save in Guettardeae); embryo straight or rarely curved, the radicle mostly longer than the cotyledons

Zappi, D. (2009). Neotropical Rubiaceae.

Morphology

Description

Herbs, climbers , lianas, shrubs, trees, usually understorey shrubs. Leaves opposite, sometimes whorled , entire , linked by interpetiolar (sometimes intrapetiolar ) stipules of varied shapes and sizes, with colleters within. Inflorescences variable, panicles, cymes, racemes, fascicles, terminal or axillary , sometimes flowers solitary, bracts often present, sometimes corolline or involucral. Flowers 4-5(-6-12) merous , hermaphrodite or bisexual , often heterostylic or with secondary pollen presentation (when bisexual ); calyx fused with hypanthium, free part tubular or lobed , sometimes very short, in some genera one calyx -lobe developed as a semaphyll; corolla gamopetalous, aestivation valvate , imbricate , contorted , mostly radial (rarely zygomorphic ), small to 15(-30) cm long, white, cream, yellow, pink, blue, red, violet or mauve, sometimes bi-coloured, glabrous to hairy outside or within, stamens alternate to the corolla -lobes, stigma undivided to more commonly 2- lobed . Fruits capsular, berry -like or drupaceous with 1-many pyrenes; seeds 1-numerous, rounded , angled or winged .

General Description

Notes on delimitation

• Includes Dialypetalanthus Kuhlm. (formerly Dialypetalanthaceae).

Number of genera

• 637 genera and over 10,000 species worldwide, of which approximately 220 genera and 4,500 species are Neotropical.

Status

• Exotic species of Ixora L. from China
• Several species and cultivars of Mussaenda L., Gardeniajasminoides Ellis and Pentaslanceolata Schum. are widely cultivated ornamental plants in the Neotropics.
• Species of cultivated Coffea L. commonly escape into forests near farms in Brazil.
• Species of Cinchona L. cultivated for quinine have been introduced in many tropical countries.
• Genipaamericana L. is cultivated throughout South America for edible fruits and dye.
• Weedy genera such as Galium L., Borreria G.Mey., Diodia L., Richardia L.and Mitracarpus Zucc. have distribution sometimes worldwide.
• Endemic genera in the Caribbean are often monotypic.

General notes

• One of the most important plant families from the Neotropics, it occupies between 3rd and 5th place in species richness in tropical forests.

Distribution

Distribution in the Neotropics

• Throughout the Neotropics, 3rd to 5th family in number of species in tropical forests.

Diagnostic

Other important characters

• Colleters in the inside of stipules and calyx.
• Secondary pollen presentation in Gardenieae.
• Herbs with varied capsular fruits in Spermacoceae.
• Pyrenes and raphids in some groups.

Distinguishing characters (always present)

• Simple, opposite (rarely whorled) leaves with entire margin.
• Interpetiolar and sometimes intrapetiolar stipules.
• Corolla gamopetalous (exc. Dichapetalanthus).
• Ovary inferior (exc. Pagamea Aubl.).

Key differences from similar families

• Inferior ovary sets apart from Loganiaceae and Gentianaceae.
• Corolla generally radial separates from Campanulaceae, Acanthaceae and Lamiales.

Notable genera and distinguishing features

• Borreria (= Spermacoce) G. Mey.: herbs to subshrubs, stipules fringed, flowers tetramerous, 2-seeded capsules.
• Cinchona L.: trees, corolla long, pinkish, many ovules per locule, seeds winged in capsules.
• Faramea Aubl.: shrubs to trees, stipules aristate or triangular, flowers blue, fruits 1-seeded.
• Genipa L.: trees, pre-floration contorted, flowers bisexual, secondary pollen presentation, large berries with fleshy pulp.
• Manettia Mutis ex L.: twining climber with showy flowers, many-seeded capsular fruit.
• Palicourea Aubl.: shrubs to treelets, bilobed to bifid stipules, flowers colourful, corolla tube gibbose, fruits 2-5-seeded, fleshy.
• Psychotria L.: shrubby to tree-like, bilobed or rounded stipules, corolla tube straight, flowers small, white, cream or yellow, fruits 2-5-seeded, fleshy.
• Rudgea Salisb.: shrubs to trees, stipules fringed to appendiculate, corolla tube straight, often longer than Psychotria.

Useful tips for generic identification

• Number of locules.
• Ovules per locule.
• Type of fruit.
• Presence of pyrenes.
• Aestivation.
• Habit would help to place the specimen within a subfamily or tribe.

Literature

Important literature

Andersson, L. 1992. A Provisional Checklist of Neotropical Rubiaceae. Scripta Botanica Belgica 1.

Müller, J. 1881-1888. Rubiaceae. In Martius, C.F.P. von (ed.). Fl. bras. 6(5):  1-486. Fleischer, Leipzig.

Schumann, K. 1888-1889. Rubiaceae. In Martius, C.F.P. von & Eichler, A.G (eds.). Fl. bras. 6(6): 1-466. Fleischer, Leipzig.

Taylor, C.M., Steyermark, J.A., Delprete, P.G., Vincentini, A., Cortés, R., Zappi, D., Persson, C., Costa, C.B. & Anunciação, E. 2004. Rubiaceae. In: Steyermark, J.A., Berry, P.E., Yatskievych, K., & Holst, B.K. (eds.). Flora of the Venezuelan Guayana 8: 497-847.

Rubiaceae, F.N. Hepper & R.W.J. Keay. Flora of West Tropical Africa 2. 1963

Morphology General Habit

Trees, shrubs or rarely herbs

Morphology Leaves

Leaves opposite or rarely verticillate, entire; stipules inter- or intra-petiolar, often connate, rarely leafy and not distinguishable from the leaves

Morphology Reproductive morphology Flowers

Flowers usually hermaphrodite, actinomorphic or very rarely slightly zygomorphic, solitary to capitate

Morphology Reproductive morphology Flowers Calyx

Calyx adnate to the ovary

Morphology Reproductive morphology Flowers Corolla

Corolla epigynous, more or less tubular, rarely campanulate; lobes 4-12, contorted, imbricate or valvate

Morphology Reproductive morphology Flowers Androecium

Stamens epipetalous, as many as and alternate with the corolla-lobes; anthers mostly separate, 2-celled, opening lengthwise or rarely by terminal pores, rarely transversely septate

Morphology Reproductive morphology Flowers Gynoecium

Ovary inferior or rarely superior, 2- or more-celled, with axile, apical or basal placentas, or rarely 1-celled with parietal placentas; style often slender; ovules 1 to many

Morphology Reproductive morphology Fruits

Fruit a capsule, berry or drupe

Morphology Reproductive morphology Seeds

Seeds rarely winged, mostly with endosperm, the latter rarely ruminate; embryo straight or curved