Neotropical Cucurbitaceae

Nigel P. Taylor and Daniela Zappi

Royal Botanic Gardens, Kew, UK. 

Description

Climbing or scrambling vines, sometimes woody lianas, rarely decumbent shrubs, almost never self-supporting; tendrils originated from branches and alternate to the leaves, often branched, sometimes absent. Stipules absent. Leaves generally petiolate, sometimes scabrous, generally with foetid or rank smell, venation generally palmate, entire to lobed, sometimes compound, margin entire, crenate or dentate, base often cordate, with a broad sinus. Inflorescences axillary, racemose or paniculate, rarely subumbellate (Gurania Cogn.), often reduced to a showy, solitary flower. Flowers unisexual in dioecious or monoecious plants, radially symmetric, epigynous; calyx (3-)5-merous, lobes fused or free; corolla (3-)5-merous, lobes fused or free, white, cream, yellow, orange, rarely red or pink; stamens (1-)3-5, fused to the hypanthium and adnate or free, anthers dehiscing longitudinally; ovary inferior, placentation parietal, less commonly basal or apical, style present, normally one, generally stout, sometimes 3, stigmas bifid. Fruit normally a hard-skinned berry known as a pepo, green, white, yellow, orange or tinged with red, often spotted or striped, sometimes soft-walled, small berries (Melothria L., some Cayaponia Silva Manso), sometimes fleshy capsules with irregular, explosive dehiscence (Cyclanthera Schrad., Ecballium A.Rich.), rarely capsular or samaroid, 1-many seeded; seeds generally tear-shaped and flattened, but sometimes with irregular margins and varied ornamentation, embryo oily and endosperm lacking.

Notes on delimitation

  • Together with the Begoniaceae, Cucurbitaceae is currently placed within order Cucurbitales (APG II, 2003, Souza & Lorenzi 2005).

Distribution in the Neotropics

  • Widely distributed in the Neotropics, represented by over 30 native genera and 8 introduced (see below).

Distinguishing characters (always present)

Other important characters

Key differences from similar families

Number of genera

Neotropical:

  • Abobra tenuifolia Naudin, cultivated as ornamental.
  • Apodanthera Arn. 15 spp.
  • Calycophysum Karst. & Triana 6 spp.
  • Cayaponia 45 spp.
  • Ceratosanthes Burm. ex Adans. 1 sp.
  • Cucurbita L. 27 spp., C. pepo (squashes and marrows), C. maxima (pumpkin), C. moschata (butternut squash).
  • Cucurbitella Walp. 2 spp.
  • Cyclanthera 15 spp.
  • Doyerea Grosourdy 1 sp.
  • Echinopepon Naudin 12 spp.
  • Elateriopsis Ernst 6 spp.
  • Fevillea L. 7 spp.
  • Gurania 1 sp.
  • Helmontia Cogn. 1 sp.
  • Melancium Naudin 1 sp.
  • Melothria 10 spp.
  • Melothrianthus Mart.Crov. 1 sp.
  • Posadaea Cogn. 1 sp.
  • Pseudocyclanthera Mart.Crov. 1 sp.
  • Pseudosicydium Harms 1 sp.
  • Psiguria Neck. 15 spp.
  • Pteropepon Cogn. 3 spp.
  • Rytidostylis Hook. & Arn. 5 spp.
  • Sechium P.Browne 5 spp., S. edule (Chayote or Chuchu)
  • Selysia Cogn. 3 spp.
  • Sicana odorifera Naudin, edible fruit known as Cruá.
  • Sicydium Schltdl. 6 spp.
  • Sicyos L. 25 spp.
  • Siolmatra Baill. 3 spp.
  • Wilbrandia Silva Manso 2 spp.

Introduced:

  • Benincasa hispida (Thunb.) Cogn. - cultivated.
  • Citrullus lanatus (Thunb.) Matsumura & Nakai - watermelon.
  • Cucumis pepo Dumort. - cucumber.
  • Ecballium elaterium (L.) A.Rich. - squirting cucumber.
  • Lagenaria siceraria (Molina) Standl. - bottle gourd or calabash.
  • Luffa aegyptiaca Mill. - luffa or vegetable sponge.
  • Momordica charantia L. - invasive.
  • Peponopsis spp. Naudin - naturalized.
  • Trichosanthes spp. L. - naturalized.

Useful tips for generic identification

  • Tendril ramification.
  • Flower size and colour.
  • Fusion and shape of calyx and corolla -lobes.
  • Shape and disposition of stamens.
  • Styles fused or free.
  • Fruit type.
  • Placentation.
  • Number of seeds per fruit.

(Jeffrey & Trujillo 1992, Gentry 1996).

Notable genera and distinguishing features

  • Cucurbita - Showy yellow flowers, ovary many-ovulated, fruit a pepo.
  • Sechium - Small greenish flowers, ovary uniovulated, fruit drupaceous.
  • Gurania - Forest liana with showy orange/yellow flowers arranged in pseudo-umbels.
  • Cayaponia - Forest liana with cream-coloured flowers, ovary 2-5-ovulated, ovules pendulous, fruit a berry.
  • Cyclanthera - Delicate climber, flowers small and white or cream, fruit clavate and explosive, spiny, seeds ruminated at the edges.
  • Lagenaria Ser. - Flower white, fruit elongated, bottle-shaped.
  • Luffa Mill. - Flowers yellow, medium sized, fruit cylindric, fibrous inside, sometimes operculated.

Status

  • Approximately 120 genera and 760 species with mostly tropical distribution, as they do not tolerate sub -zero temperatures.
  • Of these, around 30 genera and over 400 species occur in the Neotropics.
  • Cultivated genera of Neotropical origin (Cucurbita) and introduced ones (Cucumis L., Citrullus Schrad.) are of major importance as food and forage crops.
  • Some species, such as Momordica charantia, are invasive.

General notes

  • Easy to recognize at family level, the difficulties of determining Cucurbitaceae to genus and species are mainly caused by their unisexual flowers borne in different types of inflorescences (female flowers tend to be large, solitary and axillary, while the male inflorescences are racemose or paniculate and the flowers are smaller and early deciduous).
  • Matching specimens with female flowers, male flowers and fruit has always been a challenge and authors provide keys for flowering AND fruiting specimens (Jeffrey & Trujillo 1992).
  • The family was radically revised by Jeffrey (1980), who subdivided it in two subfamilies Cucurbitoideae and Zanonioideae based on fusion of stigmas and tendril morphology.
  • Cucurbitoideae has been further subdivided into tribes.
  • Due to its economic importance, the genus Cucurbita has been studied in detail from the point of view of its domestication (Nee 1990).

Important literature

APG II, 2003. An update of the Angiosperm Phylogeny group classification for the orders and families of flowering plants: APG II. Botanical Journal of the Linnean Society 141(4): 399-436.

Gentry, A.H. 1996. A field guide to the families and genera of Woody Plants of Northwest South America (Colombia, Ecuador, Peru). The University of Chicago Press, Chicago and London.

Jeffrey, C. 1980. A review of the Cucurbitaceae. Bot. J. Linn. Soc. 81: 233-247.

Jeffrey, C. & Trujillo, B. 1992. Cucurbitaceae in Flora de Venezuela 5(1): 1 - 201.

Nee, M. 1990. The Domestication of Cucurbita. Economic Botany 44(suppl. 3): 53 - 68.

Souza, V.C. & Lorenzi, H. 2005. Botânica Sistemática: guia ilustrativo para identificação das famílias de Angiospermas da flora brasileira, baseado em APG II. Nova Odessa, Brazil: Instituto Plantarum.

How to cite

Taylor, N. & Zappi, D. (2009). Neotropical Cucurbitaceae. In: Milliken, W., Klitgård, B. & Baracat, A. (2009 onwards), Neotropikey - Interactive key and information resources for flowering plants of the Neotropics. http://www.kew.org/science/tropamerica/neotropikey/families/Cucurbitaceae.htm.