DELTA home

The families of flowering plants

L. Watson and M.J. Dallwitz

Asteranthaceae Knuth

~ Lecythidaceae or Scytopetalaceae.

Habit and leaf form. Trees. Leaves alternate; spiral, or distichous (?); leathery; simple. Lamina entire. Leaves stipulate. Stipules free of one another; caducous (and minute). Lamina margins entire.

General anatomy. Plants with silica bodies (?).

Leaf anatomy. The leaf lamina dorsiventral, or centric. Stomata present; mainly confined to one surface (abaxial); anisocytic. Lamina without secretory cavities. The mesophyll with sclerenchymatous idioblasts.

Axial (stem, wood) anatomy. The cortex without cristarque cells. Secretory cavities absent. Cork cambium present; initially superficial. Primary vascular tissues in a cylinder, without separate bundles; collateral. Internal phloem absent. Cortical bundles present (with normal orientation). Secondary thickening developing from a conventional cambial ring.

The wood diffuse porous. The vessels moderately small to medium. The vessel end-walls simple. The vessels without vestured pits. The axial xylem without fibre tracheids; with libriform fibres. The parenchyma in numerous short, irregular, almost diffuse lines; wood not storied.

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

Inflorescence, floral, fruit and seed morphology. Flowers solitary; axillary; large; regular. Free hypanthium absent. Hypogynous disk present (large, plicate, dentate, membranous, representing connate staminodes); extrastaminal.

Perianth sepaline (the anthoecial tube within it constituting a pseudocorolla); disciform; joined; 1 whorled. Calyx disciform; 1 whorled; gamosepalous (leathery); entire, or lobulate to blunt-lobed (by tearing during anthesis); persistent; accrescent (constituting a flotation device for the fruit).

Androecium 50–100 (or more). Androecial members branched, or unbranched (?); maturing centrifugally; free of the perianth; coherent (the filaments of the stamens adnate basally to one another and to the pseudocorolla); 2 whorled (comprising an outer staminodal whorl, and the stamens in a single, dense ring, not resolvable into series). Androecium including staminodes. Staminodes 24–28 (connate); external to the fertile stamens; petaloid (connate to form the large, membranous, plicate pseudocorolla, which opens umbrella-like at anthesis). Stamens 40–100 (?—‘many’); polystemonous; filantherous (the filaments slender). Anthers basifixed; non-versatile; dehiscing via longitudinal slits; introrse. Pollen grains aperturate; 3 aperturate; colpate (colpate).

Gynoecium 6–8 carpelled. The pistil 6–8 celled. Gynoecium syncarpous; eu-syncarpous; partly inferior. Ovary 6–8 locular. Gynoecium stylate. Styles 1 (filiform); attenuate from the ovary; apical; about as long as the ovary to much longer than the ovary. Stigmas 1; 6–8 lobed; capitate. Placentation axile to apical. Ovules (3–)4(–6) per locule; funicled; pendulous to horizontal; anatropous; bitegmic; tenuinucellate.

Fruit non-fleshy; dehiscent, or indehiscent; a capsule, or capsular-indehiscent. Capsules loculicidal (6–8 valved and ribbed, pyramidal, crustaceous, surrounded by the persistent calyx). Seeds copiously endospermic. Endosperm ruminate. Seeds without starch. Seeds with amyloid. Cotyledons 2 (but small and reduced). Embryo straight to curved (somewhat hooked).

Geography, cytology. Neotropical. Tropical. Northern Brazil.

Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgren’s Superorder Theiflorae; Theales. Cronquist’s Subclass Dilleniidae; Lecythidales. APG III core angiosperms; core eudicot; Superorder Asteranae (presumably). APG IV Order unassigned (as a synonym of Lecythidaceae).

Species 1. Genera 1 (Asteranthos brasiliensis); only genus, Asteranthos.

General remarks. Appel (1966) favoured inclusion of Asteranthos in Scytopetalaceae rather than Lecythidaceae. Morton et al. (1998) refered it to subfamily Scytopetaloideae of their expanded Lecythidaceae, based on an assessment ‘using both molecular and morphological data’ In terms of the extensive data compiled for the present package, Asteranthos is much closer to Scytopetalaceae than to Lecythidaceae sensu stricto, but is sufficently different from both of them to justify separate family status.

Illustrations. • Asteranthos brasiliensis: Fl. Brasil. 12 (1879).

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.’.