The families of flowering plants

L. Watson and M.J. Dallwitz

Hoplestigmataceae Gilg

~ Boraginaceae.

Habit and leaf form. Trees; non-laticiferous. Leaves large; alternate; chartaceous; petiolate; non-sheathing; simple. Lamina entire; obovate; pinnately veined; cross-venulate; attenuate at the base. Leaves exstipulate. Lamina margins entire.

Axial (stem, wood) anatomy. Secondary thickening developing from a conventional cambial ring.

Reproductive type, pollination. Plants hermaphrodite.

Inflorescence, floral, fruit and seed morphology. Flowers aggregated in ‘inflorescences’; in cymes. The ultimate inflorescence units cymose. Inflorescences terminal; brown-hirsute, terminal subscorpioid cymes. Flowers ebracteate; medium-sized to large; regular; irregularly cyclic; irregularly polycyclic. Free hypanthium absent.

Perianth with distinct calyx and corolla; 13–18; irregularly 3–5 whorled; anisomerous. Calyx 1 whorled; gamosepalous (entire and globose in bud, splitting irregularly into 2–4 lobes); persistent (at the base of the fruit). Corolla 11–14; irregularly 2–4 whorled; gamopetalous (with a short tube). Corolla lobes about the same length as the tube, or markedly longer than the tube. Corolla imbricate; regular.

Androecium 20–35. Androecial members free of the perianth; free of one another; irregularly 3 whorled. Androecium exclusively of fertile stamens. Stamens 20–35; diplostemonous to polystemonous; filantherous (with filiform filaments). Anthers dorsifixed (near the base); dehiscing via longitudinal slits; latrorse; tetrasporangiate. Pollen shed as single grains. Pollen grains aperturate; 3 aperturate; colporate (said to resemble Ehretia).

Gynoecium 2 carpelled. Carpels reduced in number relative to the perianth. The pistil 1 celled. Gynoecium syncarpous; synovarious to synstylovarious; superior. Ovary 1 locular; sessile. Gynoecium non-stylate. Styles 2; partially joined (near the base, the pair of branches incurved to form a horseshoe shape); apical. Stigmas 2; capitate. Placentation parietal (the two placentas intruded and forked). Ovules in the single cavity 4 (two per placenta); pendulous; anatropous; unitegmic.

Fruit fleshy to non-fleshy (the exocarp leathery); indehiscent; a drupe (or drupaceous). The drupes with one stone (laterally compressed, chanelled along the narrow sides, with a bony endocarp). Fruit 4 seeded. Seeds scantily endospermic. Embryo well differentiated (rather large). Cotyledons 2 (expanded). Embryo straight to curved (nearly straight).

Seedling. Germination phanerocotylar.

Physiology, phytochemistry. Aluminium accumulation not found.

Geography, cytology. Paleotropical. Tropical. West equatorial Africa.

Taxonomy. Subclass Dicotyledonae; Tenuinucelli (gamopetalous, with unitegmic ovules). Dahlgren’s Superorder Solaniflorae; Boraginales, or Solanales (?). Cronquist’s Subclass Dilleniidae; Violales. APG 3 Order unassigned (as a synonym of Boraginaceae?).

Species 2. Genera 1; only genus, Hoplestigma.

General remarks. This description indicates numerous morphological differences from Boraginaceae, but is inadequate for reliable classification.

Illustrations. • Technical details: Hoplestigma (Hutchinson).

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: 30th September 2017.’.