Family Euryalaceae

Euryalaceae J.G. Agardh

~ Nymphaeaceae

Habit and leaf form. Large, stemless, 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 sclerencymatous idioblasts. Vessels absent.

Stem anatomy. Primary vascular tissue in scattered bundles. Secondary thickening absent. Xylem presumably with tracheids; without vessels. Pith with diaphragms.

Root anatomy. Root xylem without vessels.

Reproductive type, pollination. 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 red, or pink (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, biochemistry. 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 3 peripheral angiosperms; Superorder Nymphaeanae; Order Nymphaeales (as a synonym of Nymphaeaceae).

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