Family Pentaphragmataceae

Pentaphragmataceae J.G. Agardh

Habit and leaf form. Coarse herbs. Plants somewhat succulent. Leaves medium-sized to large; alternate; simple. Lamina entire; usually conspicuously asymmetric (at the base). Leaves exstipulate. Lamina margins entire (or sinuate), or dentate.

Leaf anatomy. Stomata more or less anomocytic (surrounded by three or four cells not very different from the rest of the epidermis). Hairs present; often multicellular. Multicellular hairs often branched.

Lamina dorsiventral; seemingly without secretory cavities.

Stem anatomy. Secretory cavities seemingly absent. Cortical bundles absent. Medullary bundles absent. Internal phloem absent. Secondary thickening developing from a conventional cambial ring. ‘Included’ phloem absent. Xylem with fibre tracheids. Vessel end-walls scalariform.

Reproductive type, pollination. Plants hermaphrodite (usually), or polygamomonoecious (? — rarely with unisexual flowers). Floral nectaries present. Nectar secretion from between the hypanthium and the gynoecium. Pollination mechanism unspecialized (by contrast with Campanulaceae).

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in cymes. The ultimate inflorescence unit cymose. Inflorescences extra-axillary or axillary; dense, sympodial helicoid cymes. Flowers conspicuously bracteate (the bracts membranous); more or less regular; more or less 5 merous; cyclic; tetracyclic. Free hypanthium present to absent (the inferior ovary being adnate to the hypanthium only by longitudinal septa more or less continued from the filaments, creating (4–)5 nectariferous channels).

Perianth with distinct calyx and corolla; (9–)10; 2 whorled; isomerous (usually), or anisomerous. Calyx 5; 1 whorled; polysepalous; unequal but not bilabiate; persistent; imbricate. Corolla (4–)5; 1 whorled; polypetalous (rarely), or gamopetalous; valvate; regular; fleshy (usually, or cartilaginous), or not fleshy (rarely delicate); persistent.

Androecium (4–)5 (equalling the petals or corolla lobes). Androecial members free of the perianth (inserted on the margins of the top of the ovary, when polypetalous), or adnate (usually); all equal; free of one another; 1 whorled. Androecium exclusively of fertile stamens. Stamens (4–)5; inserted in the throat of the corolla tube (shortly below the sinuses); isomerous with the perianth; oppositisepalous; filantherous (usually, the filaments persistent), or with sessile anthers (rarely, the filaments almost wanting). Anthers basifixed; dehiscing via longitudinal slits; introrse; tetrasporangiate. Endothecium developing fibrous thickenings. Anther epidermis persistent. Microsporogenesis simultaneous. The initial microspore tetrads tetrahedral and decussate. Anther wall initially with more than one middle layer (2); of the ‘dicot’ type. Tapetum glandular. Pollen shed as single grains. Pollen grains aperturate; (2–)3 aperturate; colporate; 3-celled (see Davis 1966).

Gynoecium 2–3 carpelled. Carpels reduced in number relative to the perianth. The pistil 2 celled, or 3 celled. Gynoecium syncarpous; eu-syncarpous; inferior. Ovary 2 locular, or 3 locular. Epigynous disk absent. Gynoecium stylate. Styles 1; apical; short and thick. Stigmas 1; clavate, or capitate (? — massive, glabrous, lacking ‘collecting hairs’). Placentation axile (the placentas bifid). Ovules 30–50 per locule (‘many’); pendulous; anatropous; unitegmic; tenuinucellate. Endothelium differentiated. Embryo-sac development Polygonum-type. Endosperm formation cellular. Embryogeny solanad.

Fruit fleshy; indehiscent; a berry (with the perianth persisting at the tip). Seeds copiously endospermic. Endosperm not oily (starchy). Seeds minute. Seeds with starch. Cotyledons 2.

Physiology, biochemistry. Alkaloids absent. Aluminium accumulation not found.

Geography, cytology. Paleotropical. Tropical. Southeast Asia, Malaysia.

Taxonomy. Subclass Dicotyledonae; Tenuinucelli. Dahlgren’s Superorder Violiflorae, or Asteriflorae (?); Violales (?); Campanulales (?). Cronquist’s Subclass Asteridae; Campanulales. APG 3 core angiosperms; core eudicot; Superorder Asteranae; campanulid; Order Asterales.

Species 30. Genera 1; only genus, Pentaphragma.