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The families of flowering plants

L. Watson and M.J. Dallwitz

Cucurbitaceae Juss.

Including Bryoniaceae Adanson ex Post & Kuntze, Fevilleaceae Pfeiff., Nandhirobeae (Nandhirobaceae) A. St-Hil., Nhandirobeae (Nhandirobaceae) A. St-Hil. corr. Endl., Zanoniaceae Dum.

Habit and leaf form. Mostly more or less scandent, juicy herbs, or shrubs (rarely). Annual, or perennial; without conspicuous aggregations of leaves; perennials in temperate regions tuberous. Climbing (mostly, or more or less trailing), or self supporting; tendril climbers (often, the tendrils representing modified shoots, usually one per node), or scrambling (the tendrils occasionally reduced to spines). Mesophytic to xerophytic. Leaves alternate; spiral; petiolate; non-sheathing; simple, or compound; when compound ternate, or palmate. Lamina dissected, or entire; when simple/dissected, palmatifid; usually palmately veined; cross-venulate. Leaves exstipulate; leaf development not ‘graminaceous’.

Leaf anatomy. The leaf lamina dorsiventral (usually), or bifacial (sometimes). Extra-floral nectaries often present. Hydathodes very commonly present. Stomata mainly confined to one surface (abaxial), or on both surfaces; anomocytic. Hairs present (in great diversity); eglandular and glandular (the latter sometimes explosive, e.g. in Cucurbita and Momordica). Cystoliths commonly present (often visible as whitish areas around the bases of hairs). The mesophyll containing crystals, or without crystals (but infrequent in or absent from many genera). The crystals when seen, mainly druses. Minor leaf veins without phloem transfer cells (Bryonia, Cucurbita).

Axial (stem, wood) anatomy. Secretory cavities absent. Cork cambium present (usually, probably), or absent (?); initially deep-seated, or initially superficial (observed to arise at different levels in assorted genera). Nodes tri-lacunar. Primary vascular tissues comprising a ring of bundles, or comprising two or more rings of bundles (often in two more or less distinct circles, those of the inner ring sometimes almost meeting near the middle of the stem); often bicollateral, or collateral (some genera exibiting exclusively collateral bundles, and elsewhere collateral strands are often present through loss of the inner phloem from initially bicollateral bundles). Internal phloem present (usually), or absent. Cortical bundles present (occasionally), or absent. Medullary bundles absent. Secondary thickening developing from a conventional cambial ring (usually or always confined to fascicular cambium, the activity of which often results in the original bundles becoming dissected by secondary ray tissue), or anomalous. The anomalous secondary thickening via concentric cambia (commonly), or from a single cambial ring.

The vessel end-walls simple. ‘Included’ phloem present (sometimes arising in unlignified xylem tissue), or absent. Tyloses present (commonly, in older stems), or absent.

Reproductive type, pollination. Plants monoecious (commonly), or dioecious (commonly), or polygamomonoecious, or hermaphrodite (rarely). Pollination entomophilous.

Inflorescence, floral, fruit and seed morphology. Flowers solitary, or aggregated in ‘inflorescences’. Inflorescences when flowers aggregated, axillary. Flowers small to large; regular (usually), or somewhat irregular. The floral irregularity most noticeably involving the androecium. Flowers cyclic; tetracyclic. Free hypanthium present.

Perianth with distinct calyx and corolla; (6–)10(–12); 2 whorled; isomerous. Calyx (3–)5(–6); 1 whorled; gamosepalous; regular; imbricate, or open in bud. Corolla (3–)5(–6); 1 whorled; polypetalous, or gamopetalous; more or less valvate (supposedly usually, commonly induplicate), or imbricate; regular; green, or white, or yellow, or orange.

Androecium 5 (‘essentially’), or 3 (ostensibly, by reduction and displacement). Androecial members branched and unbranched (commonly there are three stamens, two bifurcated and with two pairs of pollen sacs each, the other unbranched and conventional with two pollen sacs), or unbranched; usually adnate (to the hypanthium); variously coherent (by connate filaments, or in Cucurbita by cohesion of the anthers into a column), or free of one another; when coherent, commonly 1 adelphous (i.e. all the stamens joined in a central column), or 2 adelphous (4/1 in Thladiantha); 1 whorled. Androecium exclusively of fertile stamens. Stamens 3, or 5; reduced in number relative to the adjacent perianth, or isomerous with the perianth. Anthers cohering (commonly), or connivent, or separate from one another; adnate; dehiscing via longitudinal slits; extrorse; unilocular, or unilocular and bilocular (often one unilocular, the others bilocular), or bilocular; bisporangiate, or bisporangiate and tetrasporangiate, or tetrasporangiate; appendaged (via the prolonged connective), or unappendaged. Endothecium developing fibrous thickenings. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral. Anther wall initially with one middle layer, or initially with more than one middle layer. Tapetum glandular. Pollen grains aperturate; 3 aperturate, or 4–15 aperturate (to ‘many’); variously colpate, or porate, or colporate, or foraminate, or rugate; 2-celled (6 genera).

Gynoecium 1 carpelled (Cyclanthereae), or (2–)3(–5) carpelled. Carpels reduced in number relative to the perianth. The pistil 1 celled (when monomerous), or 2–3(–5) celled. Gynoecium monomerous, or syncarpous; of one carpel (Cyclanthereae), or synovarious, or synstylovarious, or eu-syncarpous; inferior. Ovary 1 locular, or 2–3(–5) locular (by joining of the usually intruded parietal placentae). Locules secondarily divided by ‘false septa’, or without ‘false septa’. Gynoecium stylate. Styles 1, or 2–3(–5); when more than one, partially joined; apical. Stigmas 1, or 2–3(–5) (one per carpel); commissural; each 2 lobed (in association with the commissural position, suggestive of derivation from adjacent carpels); wet type, or dry type; papillate, or non-papillate; Group II type and Group III type. Placentation parietal (usually); when the ovary plurilocular, axile. Ovules in the single cavity when unilocular, (1–)3–100 (i.e. to ‘many’); when plurilocular (1–)3–50 per locule (?); pendulous, or horizontal, or ascending; non-arillate; anatropous; bitegmic; crassinucellate. Outer integument not contributing to the micropyle. Embryo-sac development Polygonum-type, or Allium-type. Polar nuclei fusing only after one has been fertilized, or fusing simultaneously with the male gamete (?). Antipodal cells formed; 3; not proliferating; ephemeral. Synergids hooked. Hypostase present, or absent. Endosperm formation nuclear. Endosperm haustoria present (usually), or absent; chalazal. Embryogeny onagrad.

Fruit fleshy (usually), or non-fleshy (sometimes); dehiscent (sometimes explosively so), or indehiscent; a berry (usually, most commonly in the form of a ‘gourd’ (pepo) or an amphisarca), or a capsule, or a samara (rarely). Seeds non-endospermic; medium sized to large; often flattened, winged, or wingless. Embryo very well differentiated (the plumule often with clear leaves). Cotyledons 2; flat (flat, often clearly veined). Embryo achlorophyllous (9/11); straight.

Seedling. Germination phanerocotylar, or cryptocotylar.

Physiology, phytochemistry. C3 and CAM. C3 physiology recorded directly in Citrullus, Cucumis, Cucurbita. CAM recorded directly in Seyrigia, Xerosicyos. Cyanogenic (rarely), or not cyanogenic. Alkaloids present (commonly), or absent. Iridoids not detected. Saponins/sapogenins present. Proanthocyanidins absent. Flavonols present, or absent; kaempferol and quercetin, or quercetin. Ellagic acid absent (4 species, 4 genera). Aluminium accumulation not found. Sieve-tube plastids S-type.

Geography, cytology. Temperate (warm only), sub-tropical to tropical. Wanting only in colder regions. X = 7–14.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Violiflorae; Violales. Cronquist’s Subclass Dilleniidae; Violales. APG III core angiosperms; core eudicot; Superorder Rosanae; fabid. APG IV Order Cucurbitales.

Species 640. Genera 120; Abobra, Acanthosicyos, Actinostemma, Alsomitra, Ampelosycios, Anacaona, Apatzingania, Apodanthera, Bambekea, Benincasa, Biswarea, Bolbostemma, Brandegea, Bryonia, Calycophysum, Cayaponia, Cephalopentandra, Ceratosanthes, Chalema, Cionosicyos, Citrullus, Coccinia, Cogniauxia, Corallocarpus, Cremastopus, Ctenolepis, Cucumella, Cucumeropsis, Cucumis, Cucurbita, Cucurbitella, Cyclanthera, Dactyliandra, Dendrosicyos, Dicoelospermum, Dieterlea, Diplocyclos, Doyerea, Ecballium, Echinocystis, Echinopepon, Edgaria, Elateriopsis, Eureiandra, Fevillea, Gerrardanthus, Gomphogyne, Gurania, Guraniopsis, Gymnopetalum, Gynostemma, Halosicyos, Hanburia, Helmontia, Hemsleya, Herpetospermum, Hodgsonia, Ibervillea, Indofevillea, Kedrostis, Lagenaria, Lemurosicyos, Luffa, Marah, Melancium, Melothria, Melothrianthus, Microsechium, Momordica, Muellerargia, Mukia, Myrmecosicyos, Neoalsomitra, Nothoalsomitra, Odosicyos, Oreosyce, Parasicyos, Penelopeia, Peponium, Peponopsis, Polyclathra, Posadaea, Praecitrullus, Pseudocyclanthera, Pseudosicydium, Psiguria, Pteropepon, Pterosicyos, Raphidiocystis, Ruthalicia, Rytidostylis, Schizocarpum, Schizopepon, Sechiopsis, Sechium, Selysia, Seyrigia, Sicana, Sicydium, Sicyos, Sicyosperma, Siolmatra, Siraitia, Solena, Tecunumania, Telfairia, Thladiantha, Trichosanthes, Tricyclandra, Trochomeria, Trochomeriopsis, Tumacoca, Vaseyanthus, Wilbrandia, Xerosicyos, Zanonia, Zehneria, Zombitsia, Zygosicyos.

General remarks. Review of family: Jeffrey 1980.

Economic uses, etc. Many sources of important edible fruits, e.g. Cucurbita, Cucumis, Lagenaria, Sechium (melons, cucumbers, etc.), and some are poisonous.


We’ll use this unwholesome humidity, this gross watery pumpion; we’ll teach him to know turtles from jays
(‘Merry Wives’, iii., 3 - metaphore for empty-headed)

Illustrations. • Le Maout and Decaisne: Cucumis, Cyclanthera, Sechium, Echinocystis. • Bolbostemma biglandulosum, as Actinostemma: Hook. Ic. Pl. 27 (1899). • Bryonia dioica (J. E. Sowerby, 1861). • Bryonia dioica: Eng. Bot. 517 (1865). • Female Hodgsonia heteroclita, with details of flowers and fruit: Hooker’s Illustrations of Himalayan plants (1855). • Hodgsonia heteroclita (a male flowering plant and details of male and female flowers): Hooker’s Illustrations of Himalayan plants (1855). • Hemsleya chinensis: Hook. Ic. Pl. 19 (1889). • Luffa cylindrica. as L. pentandra: R. Wight, Ic. Pl. Indiae Orientalis 2 (1843). • Momordica charantia: Thonner.

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, genera included in each family, and classifications (Dahlgren; Dahlgren, Clifford, and Yeo; Cronquist; APG). See also Guidelines for using data taken from Web publications.

Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The families of flowering plants: descriptions, illustrations, identification, and information retrieval. Version: 15th April 2018.’.