Lythraceae J.St.-Hil.

Gemma Bramley, Anna Trias-Blasi & Richard Wilford (2023). The Kew Temperate Plant Families Identification Handbook. Kew Publishing Royal Botanic Gardens, Kew

Recognition

Characters of similar families: Onagraceae: pollen grains usually connected by viscin threads, ovary inferior.

Morphology General Habit

Herbs, annual or hardy, sub-shrubs or occasionally aquatics

Morphology Leaves Stipules

Stipules absent

Morphology Leaves

Leaves simple, opposite, alternate, or in whorls, margins entire

Morphology Reproductive morphology Flowers

Flowers axillary, solitary or in axillary glomerules or terminal spikes, bisexual, actinomorphic or nearly so; calyx fused, contributing to a tubular hypanthium, lobes free, 8–12 parts in 2 alternating rows; corolla of 4–6 petals, sometimes clawed, inserted at the margin of the hypanthium, alternating with the divisions of the calyx; stamens 6–12 inserted within the hypanthium, sometimes dimorphic; ovary superior, style single, fililform, stigma entire, capitate sometimes bilobed

Morphology Reproductive morphology Fruits

Fruit free, capsular, membranous, bilocular, with 4–5 locules and many ovules, tearing irregularly or loculicidal in two, sometimes more valves

Morphology Reproductive morphology Seeds

Seeds inserted along axile placentas

Morphology Reproductive morphology

Breeding systems can be hetero- or tri-stylous.

Distribution

Lythraceae is a family of 28 genera and ca. 625 species, with several genera common in temperate zones but most species occurring in the tropics.

Note

Herbs or sub-shrubs. Leaves simple, opposite, alternate or whorled, margins entire. Calyx tubular with free lobes, petals often clawed, inserted on rim of floral tube. Ovary superior or semi-inferior. Fruits capsular or loculicidal with many seeds.

Description Author

Eve Lucas

Timothy Utteridge & Gemma Bramley (2020). The Kew Tropical Plant Families Identification Handbook, Second Edition. Kew Publishing Royal Botanic Gardens, Kew

Note

Leaves opposite, simple, margins entire. Flowers with perigynous floral tube with crinkled petals inserted at rim; stamens in two whorls; ovary usually superior. Fruit usually capsular, many seeded.

Recognition

Characters of similar families: Combretaceae: ovary inferior, placentation apical. Malpighiaceae: calyx with glands, sepals usually free, stamens in a single whorl. Myrtaceae: stamens numerous, ovary inferior. Onagraceae: flowers epigynous, ovary inferior. Rubiaceae: interpetiolar stipules distinct, stamens 4–5, ovary inferior.

Morphology General Habit

Trees, shrubs or herbs, young stems often quadrangular

Morphology Leaves Stipules

Stipules minute or absent; bark often flaky

Morphology Leaves

Leaves opposite, rarely whorled or alternate; simple; lamina margins entire

Morphology Reproductive morphology Inflorescences

Inflorescences in cymes, or racemes, spikes or thyrses, terminal or axillary, seldom solitary

Morphology Reproductive morphology Flowers

Flowers bisexual, actino- or zygomorphic; typically perigynous with floral tube campanular to tubular, often strongly nerved, 4–6(8–16)-merous, often with small appendages between lobes; petals (0–)4–6(–many), inserted at rim of floral tube, alternating with sepals, crinkled, frequently clawed; stamens twice as many as petals, or numerous, in two whorls, mono- or dimorphic, inserted near base of floral tube or above; ovary superior, seldom semi-inferior to inferior, 2–4(–many) fused carpels, each forming a locule, ovules 2–many, placentation axile; single style and stigma

Morphology Reproductive morphology Fruits

Fruit a capsule exceeding or enclosed by persistent floral tube, rarely berry-like; dehiscence loculicidal, septicidal or irregular, rarely indehiscent

Morphology Reproductive morphology Seeds

Seeds many, typically small, morphologically diverse.

Distribution

31 genera and c. 650 species found in the subtropics and tropics with some temperate representatives. Cuphea (c. 250 species) is the largest genus. Lagerstroemia indica (crepe myrtle) is a common tropical street tree. Lawsonia inermis (henna) is a dye plant. The family now includes Punica granatum (pomegranate) and Trapa natans (water chestnut), as well as the Sonneratiaceae (Sonneratia spp. are mangrove trees).

Description Author

Gemma Bramley and Eve Lucas

Lythraceae, B. Verdcourt. Flora of Tropical East Africa. 1984

Morphology General Habit

Annual or perennial herbs, subshrubs, shrubs or trees

Morphology Leaves

Leaves simple, opposite or verticillate, rarely alternate; stipules absent or minute

Morphology Reproductive morphology Flowers

Flowers regular or slightly irregular, hermaphrodite, (3–)4, 6, 8(–16)-merous, solitary to paniculate, sometimes di- or tri-morphic

Morphology Reproductive morphology Flowers Calyx

Sepals united into a tube (hypanthium), lobes valvate, often with small appendages between

Morphology Reproductive morphology Flowers Corolla

Petals free, inserted towards the top of the calyx-tube, alternating with the sepals, folded in bud, or absent

Morphology Reproductive morphology Flowers Androecium

Stamens usually 4 or 8, less often many (10–200) or fewer (1–2), inserted below the petals; filaments sometimes of different lengths in the different forms of flower, usually inflexed in bud; anthers 2-thecous, opening lengthwise

Morphology Reproductive morphology Flowers Gynoecium

Ovary superior (except Punica), sessile or shortly stipitate, completely or incompletely 2–6-locular, rarely unilocular or multilocular (>i>Punica); style simple, sometimes of different lengths in different forms of flower; stigma often ± capitate; ovules 2–numerous on axile placentas sometimes not reaching apex of ovary (parietal in one >i>Ammannia)

Morphology Reproductive morphology Fruits

Fruit capsular or baccate, opening by a transverse slit or valves or bursting irregularly or ± indehiscent

Morphology Reproductive morphology Seeds

Seeds numerous, without endosperm

Lythraceae, A. Fernandes. Flora Zambesiaca 4. 1978

Morphology General Habit

Annual or perennial (sometimes marshy or aquatic) herbs, suffrutices, shrublets, shrubs or trees

Morphology Leaves

Leaves simple, entire, 1-nerved or ± distinctly penninerved, decussate, sometimes verticillate, rarely alternate; stipules 0 or 2–10 or more, small, subulate, axillary

Morphology Reproductive morphology Flowers

Flowers bisexual, actinomorphic or very rarely zygo-morphic, (3)4–5(6–16)-merous, homomorphic or often di-trimorphic

Morphology Reproductive morphology Inflorescences

Inflorescence various from single axillary flowers to fasciculate, cymose or paniculate; pedicels usually bracteolate

Morphology Reproductive morphology Flowers Calyx

Calyx persistent, tubular, urceolate or campanulate, the lobes alternating often with ± developed appendages in the sinuses

Morphology Reproductive morphology Flowers Corolla

Petals inserted in the calyx-tube, as many as and alternating with the calyx-lobes, sometimes few or 0, often clawed, membranous, corrugated and imbricate in the bud, equal or sometimes unequal

Morphology Reproductive morphology Flowers Androecium

Stamens numerous (32–200) in the primitive woody genera, often as many as the calyx-lobes, sometimes fewer (2 or 1) in the more advanced herbaceous ones, equal or sometimes very unequal (in heterostylous plants), inserted on the calyx-tube; filaments free; anthers 2-locular, bent inwards in the bud, dorsifixed and versatile, rarely basifixed (Pleurophora and Crimea, not from FZ area), dehiscing by longitudinal slits

Morphology Reproductive morphology Flowers Nectaries

Disk absent or very small, cupular or unilateral

Morphology Reproductive morphology Flowers Gynoecium

Ovary usually free, sessile or stipitate, 2–6-locular or 1-locular (Cryptotheca); placentation axile, rarely basal, sometimes the central axis not reaching to the top of the ovary; style absent, short or elongate and flexuous; stigma capitate or punctiform, rarely 2-lobed; ovules numerous to 2, small, anatropous, ascending

Morphology Reproductive morphology Fruits

Fruit mostly a capsule included in the calyx-tube or ± exserted, indehiscent or opening loculicidally or septicidally by valves or by a transverse lid or irregularly, with the placentas forming a central column

Morphology Reproductive morphology Seeds

Seeds 2-numerous, various in form, small, sometimes winged; embryo straight, with endosperm; cotyledons flat or rarely convolute

M. Thulin et al. Flora of Somalia, Vol. 1-4 [updated 2008] https://plants.jstor.org/collection/FLOS

Morphology General Habit

Herbs (often in or near water), shrubs and trees

Morphology Leaves

Leaves usually opposite, simple, entire; stipules minute or absent

Morphology Reproductive morphology Inflorescences

Inflorescences usually cymose, sometimes congested into raceme-like thyrses

Morphology Reproductive morphology Flowers

Flowers bisexual, usually regular, (3–)4–6(–16)-merous, sometimes heterostylous with individuals differing in the relative lengths of stamens and style

Morphology Reproductive morphology Flowers Calyx

Sepals and petals inserted on a tubular or campanulate “hypanthium” (the “calyx” or “perianth-tube” of some authors); sepals triangular, often with the sinuses between them produced into appendage-like horns

Morphology Reproductive morphology Flowers Corolla

Petals, when present, delicate, often with claw, crumpled in bud, red, pink to purple or white, soon falling

Morphology Reproductive morphology Flowers Androecium Stamens

Stamens usually up to twice as many as sepals, more in some woody genera, inserted on hypanthium, bending inwards; disc absent or very small

Morphology Reproductive morphology Flowers Gynoecium Ovary

Ovary usually superior, (1–)2–6(–8)-celled; placentation axile, rarely basal; ovules 2–many; style simple

Morphology Reproductive morphology Fruits

Fruit usually a capsule, often included within hypanthium

Morphology Reproductive morphology Seeds

Seeds usually small and numerous.

Distribution

About 28 genera and 680 species, mostly in the tropics and subtropics, less numerous in the temperate regions.

Milliken, W., Klitgard, B. and Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics. http://creativecommons.org/licenses/by/3.0

Morphology General Habit

Trees, shrubs or herbs, younger stems often quadrangulate

Morphology Leaves

Leaves opposite, less often whorled or subalternate, simple, entire, estipulate, colleters present in leaf axils; blades membranous or coriaceous, venation brochidodromous

Morphology Reproductive morphology Inflorescences

Inflorescences indeterminate, racemes, cymes, or clusters, rarely flowers solitary; pedicels with prophylls (bracteoles)

Morphology Reproductive morphology Flowers

Flowers actinomorphic or zygomorphic, perfect, perigynous, (4)- 4-6 -(16)- merous; floral tube campanulate to tubular, often conspicuously veined, persistent except in Lafoensia; sepals valvate, petals (0)-4-6(-many), inserted on the inner rim of floral tube, alternating with sepals, crinkled, pinnately veined, caducous; stamens diplostemonous, sometimes reduced to a single whorl; gynoecium syncarpous, nectariferous tissue present or absent; style simple, slender, commonly exserted, stigma capitate or punctiform; ovary superior, infrequently semi-inferior, (2)-2-4(-many) locular, septa incomplete at apex or vestigial, reduced to thin threads, placentation axile, or globose and nearly free -central

Morphology Reproductive morphology Fruits

Fruits dry, thin or thick-walled capsules enclosed by persistent floral tube, dehiscing loculicidally, septicidally, or splitting irregularly

Morphology Reproductive morphology Seeds

Seeds numerous, obpyramidal, or oblong to obovoid and concave-convex, or bilaterally lenticular- compressed, winged or not, with inverted epidermal trichomes in seed coat; embro straight, cotyledons planar, auriculate or cordate, oily.  x = 8.

Distribution

Adenaria Kunth (1/1 sp.) - limited to South America and Central America. Ammannia L. (4/25 spp.) - Old world and New World distribution. Crenea Aubl. (2/2 spp.) - New World only. Cuphea P. Browne (c. 240/c. 240 spp.) - limited to South America, Central America, Mexico, Caribbean, and United States. Diplusodon Pohl (85/85 spp.) - New World only. Ginoria Jacq. (13/13 spp.) - present in Greater Antilles and Mexico. Heimia Link (3/3 spp.) - limited to South America, Central America, Mexico, Caribbean, and United States. Lafoensia Vand. (c. 5/c. 5 sp.) - limited to South America and Central America. Lourtella Graham, Baas, & Tobe (1/1 sp.) - New World only. Lythrum L. (2/35 spp.) - Old world and New World distribution. Nesaea Comm. (3/c. 50 spp.) - Old world and New World distribution. Pehria Sprague (1/1 sp.) - limited to South America and Central America. Physocalymma Pohl (1/1 sp.) - New World only. Pleurophora D. Don (c. 6/c. 6 spp.) - New World only. Rotala L. (2/44 spp.) - Old world and New World distribution. Three non-native genera cultivated in the Neotropics: Lagerstroemia (crape myrtle), Lawsonia (henna), Punica (pomegranate).

Diagnostic

Opposite entire leaves. Flowers 4-6-merous, but 8-merous in Physocalymma, up to 16-merous in Lafoensia, perigynous, ovarysuperior, infrequently semi-inferior. Crinkled petals, often fugacious. Stamens 2-whorled (obdiplostemonous), deeply inserted. Seeds in most New World genera with inverted trichomes in the epidermal cells of the seed coat that evert on wetting: trichomes spiraled in Cuphea, Lafoensia, Pehria, Pleurophora; trichomes straight in Ammannia, Crenea, Diplusodon, Ginoria, Heimia, Lythrum, Nesaea, Rotala. Distinguishing characters (always present): No unique synapomorphies. Notable genera and distinguishing features: Cuphea - largest genus of the family, c. 240 spp.  Endemic to New World.  Unique capsule dehiscence by a longitudinal slit with placenta and seeds emerging for seed dispersal.  Seed oils emphasize lauric acids and diversity of composition includes some with major percentages of caprylic acid. Diplusodon - second largest genus of the family, c. 85 spp. Endemic to Brazil and adjacent Bolivia. Heimia -  hallucenogenic, anti-inflammatory. Key to genera of Neotropical Lythraceae 1. Leaves glandular-punctate, the punctae non-secretory and orange-filled, turning black or secretory and translucent.1. Leaves non-punctate, glabrous or variously indumented ... 4 2.  Leaves orange to black-punctate, non-secretory; inflorescences multi-flowered clusters ... 32.  Leaves translucent-punctate, secretory, blades varnished by resin; inflorescences 3-flowered axillary cymes ...Lourtella 3.  Flowers in compact umbelliform clusters; floral tube campanulate, greenish; capsule indehiscent...Adenaria3.  Flowers in loose cymose clusters; floral tube cyathiform, deep red; capsule loculicidally dehiscent...Pehria 4.  Floral tubes campanulate to globose or cyathiform, about as long as to slightly longer than wide, actinomorphic... 54.  Floral tubes cylindrical, at least twice as long as wide, actinomorphic or zygomorphic... 13 5.  Seeds encircled by a broad, thin wing — 65.  Seeds not winged... 8 6.  Floral tubes caducous, distally pleated, (8-)10-12(-16)-merous; leaves with subapical abaxial porate chamber ...Lafoensia6.  Floral tubes persistent, distally smooth, 6- or 8-merous; leaves normally developed at the apex, lacking a porate chamber ... 7 7.  Trees with strongly divaricate branching; flowers 8-merous; placenta appearing free -central ...Physocalymma7.  Shrubs and subshrubs with opposite branching; flowers 6-merous; placenta bipartite, septa lunate ...Diplusodon 8.  Trees, shrubs, or subshrubs, 1-40 m ... 98.  Annual or perennial herbs, 2 cm - 2m, commonly less than 50 cm ... 1 9.  Stamens basifixed; petals cream-coloured; capsules indehiscent... Crenea 9.  Stamens dorsifixed; petals bright yellow, rose, purple, or white ... 10 10.  Petals bright yellow; flowers solitary; pedicels 0-4 mm ...Heimia10.  Petals rose, purple, or white; flowers solitary and/or in axillary clusters; pedicels 10-40 mm ...Ginoria 11.  Capsules septicidally dehiscent, wall microscopically (10x) transversely striated; leaves decussate or whorled; leaf base tapered ...Rotala11.  Capsules splitting irregularly or initially circumscissile, then irregular; wall microscopically smooth, without striations; leaf base auriculate or auriculate... 12 12.  Capsules splitting irregularly; leaf base auriculate...Ammannia12.  Capsules initially circumscissile, then splitting irregularly; leaf base cordate...Nesaea 13.  Floral tubes actinomorphic;capsules dehiscing from the apex...Lythrum13.  Floral tubes slightly to strongly zygomorphic, bilateral; capsules indehiscent or dehiscent dorsally by a longitudinal slit together with floral tube ... 14 14.  Stamens attached near base of floral tube, anthers basifixed; capsules indehiscent, placenta and seeds retained within ... Pleurophora 14.  Stamens attached at midlevel or higher in floral tube, anthers dorsifixed; capsules dehiscent dorsally by a longitudinal slit together with floral tube, placenta and seeds exserted...Cuphea Key differences from similar families: Onagraceae differ from Lythraceae by their viscidpollen threads and, excluding Ludwigia, also by epigynous flowers with inferior ovaries.

Note

Waiting publication: Haitia synonymized with Ginoria in Graham, S. A. (2009, in press).  Revision of the Caribbean Genus Ginoria (Lythraceae), including Haitia from Hispaniola.  Ann. Missouri Bot. Garden. Notes on delimitation: Based on molecular evidence, the Combretaceae is sister to the Lythraceae and the Onagraceae. The three families constitute a major lineage of the Myrtales.  Recent molecular work has led to the expansion of the family to include the satellite families Sonneratiaceae, Duabangaceae, Punicaceae and Trapaceae. Number of genera: 15 native genera: Adenaria, Ammannia, Crenea, Cuphea, Diplusodon, Ginoria (including Haitia), Heimia, Lafoensia, Lourtella, Lythrum, Nesaea, Pehria, Physocalymma, Pleurophora, Rotala.

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

Distribution

A morphologically diverse family of about 31 genera and 620 species with a worldwide distribution including both tropical and temperate regions.

Recognition

The family has simple, opposite leaves, flowers with a perigynous floral tube with crinkled petals inserted at rim (due to the petals being crumpled in bud), a superior ovary, and a capsular fruit with many seeds.

Morphology General Habit

Herbs or sometimes shrubs or trees

Morphology Stem

Stems terete or 4-angled

Morphology Leaves Stipules

Stipules present or absent, deciduous and very small if present

Morphology Leaves

Leaves simple, usually opposite, may be alternate or whorled, petiolate or sessile, entire (dentate in Trapa), usually without gland dots, venation usually pinnate

Morphology Reproductive morphology Inflorescences

Inflorescences terminal or axillary, solitary or in cymes, panicles or racemes

Morphology Reproductive morphology Flowers

Flowers bisexual, actinomorphic or zygomorphic, usually 4–6-merous; hypanthium present, often ribbed; calyx lobes free or fused into a tube, persistent in fruit; petals free and crumpled in bud, rarely absent, usually falling early; stamens twice as many as petals or very numerous, anthers dehiscing by longitudinal slits; ovary superior, rarely inferior, 2–many-locular, 2–many ovules per locule, placentation axile, rarely parietal; hetero- or homo-stylous

Morphology Reproductive morphology Fruits

Fruit a loculicidal, septicidal or irregularly splitting, thin-walled, dry capsule, or occasionally an indehiscent berry, often partly enclosed by the hypanthium

Morphology Reproductive morphology Seeds

Seeds 2–many, embryo linear.

Lythraceae, Hutchinson and Dalziel. Flora of West Tropical Africa 1:1. 1954

Morphology General Habit

Herbs, shrubs or trees; leaves opposite or verticillate, rarely alternate; stipules absent or very small

Morphology Reproductive morphology Flowers

Flowers usually actinomorphic, hermaphrodite, solitary to paniculate

Morphology Reproductive morphology Flowers Calyx

Sepals united into a tube, valvate, sometimes with appendages between the lobes

Morphology Reproductive morphology Flowers Corolla

Petals present or absent, inserted towards the top of the calyx-tube, crumpled in the bud

Morphology Reproductive morphology Flowers Androecium

Stamens usually 4 or 8, or rarely more, inserted below the petals; filaments usually inflexed in bud; anthers 2-celled, opening lengthwise

Morphology Reproductive morphology Flowers Gynoecium

Ovary superior, sessile or shortly stipitate, completely or incompletely 2–6-celled (rarely 1-celled); style simple, variable in length; ovules numerous, on an axile placenta sometimes not extending to the top of the ovary

Morphology Reproductive morphology Fruits

Fruit usually capsular, opening by a transverse slit, by valves, or irregularly

Morphology Reproductive morphology Seeds

Seeds numerous, without endosperm; embryo straight

Sonneratiaceae, G. R. Williams Sangai (East African Herbarium). Flora of Tropical East Africa. 1968

Morphology General Habit

Trees or shrubs

Morphology Leaves

Leaves opposite, simple, entire, exstipulate

Morphology Reproductive morphology Flowers

Flowers hermaphrodite, actinomorphic, solitary or 3 together, axillary or terminal

Morphology Reproductive morphology Flowers Calyx

Calyx thick and leathery; tube campanulate; lobes 4–8, valvate

Morphology Reproductive morphology Flowers Corolla

Petals 4–8 or absent

Morphology Reproductive morphology Flowers Androecium

Stamens 12 to numerous, inserted on the calyx, often in several series; filaments free, at length reflexed; anthers reniform or oblong, medifixed, opening lengthwise

Morphology Reproductive morphology Flowers Gynoecium

Ovary free or adnate to the calyx-tube at the base, 4–many-locular; septa thin; ovules numerous, on thick axile placentas, ascending; style long, simple; stigma capitate

Morphology Reproductive morphology Fruits

Fruit a berry or a valvate capsule with 4–many locules and numerous seeds

Morphology Reproductive morphology Seeds

Seeds without endosperm; embryo with short leafy cotyledons

Sonneratiaceae, A. Fernandes. Flora Zambesiaca 4. 1978

Morphology General Habit

Trees or shrubs, with normal and sometimes aerial roots (pneumatophores)

Morphology Leaves

Leaves opposite, petiolate, coriaceous, entire, exstipulate

Morphology Reproductive morphology Flowers

Flowers bisexual, actinomorphic, solitary or in 3s, axillary or terminal

Morphology Reproductive morphology Flowers Calyx

Calyx-tube campanulate, thickly coriaceous, 4–8-lobed, the lobes valvate

Morphology Reproductive morphology Flowers Corolla

Petals 4–8 or 0

Morphology Reproductive morphology Flowers Androecium

Stamens 12 to numerous, inserted on the calyx-tube usually in several series; filaments free; anthers reniform, medifixed, opening longitudinally

Morphology Reproductive morphology Flowers Gynoecium

Ovary free or adnate at the base to the calyx-tube, 4-many-locular; septa thin; style long; stigma subcapitate; ovules numerous, embedded in thick axile placentas, ascending

Morphology Reproductive morphology Fruits

Fruit a many-seeded berry or a capsule

Morphology Reproductive morphology Seeds

Seeds without endosperm; embryo with short leafy cotyledons

Trapaceae, J. P. M. Brenan. Flora of Tropical East Africa. 1953

Morphology General Habit

Aquatic floating herbs

Morphology Leaves

Leaves alternate, floating, rosetted, only present at the upper nodes; stipules small, scarious, cleft to base and thus apparently more than two per leaf; petiole spongy and more or less inflated about the middle; lamina rhombic to deltoid

Morphology Roots

Adventitious roots (?) submerged, paired but not opposite, one from either side of leaf-scar, chlorophyllose and thus leaf-like, pinnatisect into many filiform segments

Morphology Reproductive morphology Flowers

Flowers solitary from upper axils, pedunculate, hermaphrodite, regular

Morphology Reproductive morphology Flowers Calyx

Sepals, petals and stamens 4, latter perigynous

Morphology Reproductive morphology Flowers Corolla

Petals white

Morphology Reproductive morphology Flowers Gynoecium

Ovary half-inferior, bilocular; ovules pendulous, one per loculus

Morphology Reproductive morphology Fruits

Fruit a one-seeded, top-shaped drupe; pericarp soon disappearing; endocarp very hard, variously 2–4-horned, the horns derived from the persistent sepals

Trapaceae, J.P.M.. Brenan. Flora of West Tropical Africa 1:1. 1954

Morphology General Habit

Aquatic floating herbs

Morphology Leaves

Leaves alternate, floating, resetted, only present at the upper nodes; stipules small, scarious, cleft to base and thus apparently more than two per leaf; petiole spongy and more or less inflated about the middle; lamina rhombic to deltoid

Morphology Roots

Adventitious roots (?) submerged, paired but not opposite, one from either side of leaf-scar, chlorophyllose and thus leaf-like, pinnatisect into many filiform segments

Morphology Reproductive morphology Flowers

Flowers solitary from upper axils, pedunculate, hermaphrodite, regular

Morphology Reproductive morphology Flowers Calyx

Sepals, petals and stamens 4, latter perigynous

Morphology Reproductive morphology Flowers Corolla

Petals white

Morphology Reproductive morphology Flowers Gynoecium

Ovary half-inferior, bilocular; ovules pendulous, one per loculus

Morphology Reproductive morphology Fruits

Fruit a one-seeded, top-shaped drupe; pericarp soon disappearing; endocarp very hard, variously 2–4-horned, the horns derived from the persistent sepals

Trapaceae, J. P. M. Brenan. Flora Zambesiaca 4. 1978

Morphology General Habit

Aquatic floating herbs

Morphology Leaves

Leaves alternate, floating, in rosettes, only present at the upper nodes; stipules small, scarious, cleft to base and thus apparently more than two per leaf; petiole spongy and more or less inflated about the middle; lamina rhombic to deltate

Morphology Roots

Adventitious roots (?) submerged, paired but not opposite, one from either side of petiole or leaf-scar, chlorophyllose and thus leaf-like, pinnatisect into many filiform segments; in those from upper nodes segments shorter or absent

Morphology Reproductive morphology Flowers

Flowers solitary, from upper axils, pedunculate, hermaphrodite, regular

Morphology Reproductive morphology Flowers Calyx

Sepals, petals and stamens 4, the latter perigynous

Morphology Reproductive morphology Flowers Corolla

Petals white

Morphology Reproductive morphology Flowers Gynoecium

Ovary half-inferior, bilocular; ovules pendulous, one per loculus

Morphology Reproductive morphology Fruits

Fruit a one-seeded, top-shaped drupe; pericarp soon disappearing; endocarp very hard, variously 2–4-horned, the horns derived from the persistent sepals