Habit and leaf form. Small trees, or shrubs; resinous, or not resinous. Plants unarmed. Stem internodes solid. Helophytic to xerophytic. Leaves alternate; spiral; ‘herbaceous’, or leathery; petiolate to subsessile, or sessile; non-sheathing; gland-dotted, or not gland-dotted; aromatic, or without marked odour; simple; epulvinate. Leaf blades entire; narrowly elliptic to ovate, or linear; pinnately veined; cross-venulate. Leaves without stipules; without a persistent basal meristem. Leaf anatomy. Hairs absent.
Reproductive type, pollination. Fertile flowers hermaphrodite. Unisexual flowers absent. Plants hermaphrodite. Entomophilous.
Inflorescence and flower features. Flowers aggregated in ‘inflorescences’; in panicles (or panicle-like). The terminal inflorescence unit cymose. Inflorescences terminal; leafy, centrifugal, entire terminal portion of plant given over to the inflorescence, all branches ending in a flower or aggregation of flowers. Flowers pedicellate; bracteate (opposite pair); ebracteolate (opposite pair); small to medium-sized; fragrant, or odourless; somewhat irregular to very irregular. The floral asymmetry involving the androecium, or involving the perianth and involving the androecium (the calyx regular). Flowers 5 merous; cyclic; tetracyclic. Free hypanthium absent. Hypogynous disk present; intrastaminal; annular. Perianth with distinct calyx and corolla; 10; 2 -whorled; isomerous. Calyx present; 5; 1 -whorled; gamosepalous; blunt-lobed; campanulate; regular; persistent; non-accrescent. Corolla present; 5; 1 -whorled; gamopetalous. Corolla lobes markedly shorter than the tube. Corolla contorted and plicate; campanulate; regular; white and purple (purple striations in the throat). Androecial members definite in number. Androecium 4, or 5. Androecial members adnate (epipetalous, on the tube); markedly unequal; free of one another; 1 -whorled. Androecium exclusively of fertile stamens, or including staminodes (sometimes). Staminodes 1. Stamens 4, or 5. Staminal insertion near the base of the corolla tube. Stamens all inserted at the same level; remaining included; didynamous; all more or less similar in shape; reduced in number relative to the adjacent perianth, or isomerous with the perianth; oppositisepalous (at the base of the corolla tube). Filaments appendiculate, or not appendiculate. Anthers connivent, or separate from one another; dorsifixed; dehiscing via pores to dehiscing via short slits (via a terminal, semicircular slit), or dehiscing via longitudinal slits; extrorse, or introrse; unilocular; tetrasporangiate. Pollen shed in aggregates, or shed as single grains. Gynoecium 2 carpelled. The pistil 2 celled. Gynoecium syncarpous; synstylovarious to eu-syncarpous; superior. Ovary plurilocular; 2 locular. Gynoecium oblique; stylate. Styles 1; attenuate from the ovary; apical; not becoming exserted. Stigmas 1; very shortly 2 - lobed (AKB); capitate. Placentation axile. Ovules 20–50 per locule (numerous); non-arillate; anatropous, or hemianatropous.
Fruit and seed features. Fruit fleshy; not spinose; indehiscent; a berry; 20–100 seeded (numerous, few). Seeds endospermic. Endosperm oily, or not oily. Cotyledons 2. Embryo straight, or straight to curved (no more tna slightly curved).
Special features. Corolla tube exceeding the calyx.
Etymology. Not stated in the original description; probably after Charles Du Bois (1656–1740), treasurer of the East India Company 1702–37, who had a botanical garden at Mitcham, Surrey; his herbarium is at Oxford and some specimens in the British Museum. Alternatively or additionally, Fran‡ois N”el Alexandre Dubois (1752–1824), French botanist, abbot of Orleans.