| # The Families of Angiosperms |

L. Watson and M.J. Dallwitz

### Euryalaceae J.G. Agardh

~ Nymphaeaceae.

Habit and leaf form. Large, acaulescent, prickly, aquatic herbs; laticiferous. Annual, or perennial (short lived); rhizomatous (the rhizome short, thick, erect). Hydrophytic; rooted. Leaves floating. Leaves large, or very large; alternate; petiolate; ostensibly gland-dotted (in Victoria), or not gland-dotted; simple; peltate. Lamina entire; strongly nerved. Leaves stipulate. Lamina margins turned up about 6–17 cm.

General anatomy. Plants with laticifers (articulated).

Leaf anatomy. Stomata present; mainly confined to one surface (the upper); anomocytic. The mesophyll with sclerenchymatous idioblasts (these branched, stellate, girder- or H-shaped). Foliar vessels absent.

Axial (stem, wood) anatomy. Pith with diaphragms. Primary vascular tissues of the peduncles consisting of scattered bundles (or represented by polysteles in the rhizome). Secondary thickening absent. The axial xylem without vessels.

The axial xylem with tracheids (with spiral or annular thickenings).

Root anatomy. Root xylem without vessels.

Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite.

Inflorescence, floral, fruit and seed morphology. Flowers solitary (scapiflorous); axillary; large (but small in relation to the size of the plant); fragrant; partially acyclic. The perianth acyclic and the androecium acyclic.

Perianth with distinct calyx and corolla; 50–60 (‘many’). Calyx 4; polysepalous; persistent. Corolla 40–60 (‘many’); polypetalous; imbricate; white, or pink, or red (white at first, colouring later). Petals sessile.

Androecium 100–150 (‘many’). Androecial members maturing centripetally; free of the perianth; free of one another. Androecium exclusively of fertile stamens, or including staminodes (Victoria). Staminodes of Victoria internal to the fertile stamens. Stamens 100–150 (‘many’); (sub-) petaloid. Anthers adnate; non-versatile; dehiscing via longitudinal slits; introrse (with adaxial thecae); tetrasporangiate; appendaged. Microsporogenesis simultaneous. Anther wall initially with more than one middle layer. Tapetum glandular. Pollen grains aperturate; 1 aperturate; sulcate, or zoniaperturate (?); 2-celled, or 3-celled (Euryale).

Gynoecium 6–50 carpelled (to ‘many’). The pistil 6–50 celled (to ‘many’). Gynoecium syncarpous; eu-syncarpous; inferior. Ovary 6–50 locular (to ‘many’). Epigynous disk absent. Stigmas 1 (peltate or campanulate, radiate). Placentation parietal. Ovules 30–50 per locule (‘many’); anatropous; bitegmic; crassinucellate. Outer integument not contributing to the micropyle. Embryo-sac development Polygonum-type. Antipodal cells formed; 3; not proliferating; very ephemeral. Synergids pear-shaped. Endosperm formation nuclear. Embryogeny asterad.

Fruit fleshy; indehiscent; a berry (inferior, crowned by the persistent calyx and stigma). Seeds endospermic. Perisperm present (?). Cotyledons 2. Embryo achlorophyllous (Victoria amazonica). Polyembryony recorded.

Physiology, phytochemistry. Not cyanogenic. Proanthocyanidins present.

Geography, cytology. Paleotropical and Neotropical. Tropical. Eastern Asia, tropical South America.

Taxonomy. Subclass Dicotyledonae; Crassinucelli. Dahlgren’s Superorder Nymphaeiflorae; Nymphaeales. Cronquist’s Subclass Magnoliidae; Nymphaeales. APG III peripheral angiosperms; Superorder Nymphaeanae. APG IV Order Nymphaeales (as a synonym of Nymphaeaceae).

Species 3–4. Genera 2; only genera, Euryale, Victoria.

General remarks. Seemingly differing from Nymphaeaceae sensu stricto in the fully inferior ovary and a few androecial characters, as well as the reports of nuclear endosperm and an achlorophyllous embryo. The Metcalfe and Chalk (1965) account of Nymphaeaceae sensu lato employed here does not permit satisfactory anatomical treatment of this sensu stricto family.

Illustrations. • Euryale ferox: Bot. Mag. 35 (1812). • Victoria regia, habit: Bot Mag. 73 (1847). • Victoria regia, flower: Bot Mag. 73 (1847). • Victoria regia, flower bud and LS: Bot Mag. 73 (1847). • Victoria regia, floral details in LS and TS: Bot Mag. 73 (1847).

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: 8th June 2026. delta-intkey.com’.

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