Harveya

Annual or rarely perennial herbs, holoparasitic on roots, lacking chlorophyll, coloured but mostly drying dark; stems erect or ascending, simple or branched mostly at base, usually angular, often furrowed. Leaves usually scale-like, at least lower ones, opposite or subopposite, sometimes alternate above, often close or crowded at base and upper ones more distant to scattered, sometimes few. Flowers usually large, +/- sessile to pedicellate, axillary, bracteate and bibracteolate, in terminal, lax or dense, few- to many-flowered racemes or spikes, sometimes elongating in fruit. Bracts opposite or uppermost alternate; bracteoles arising above middle to near or at pedicel apex, rarely adnate to calyx. Calyx tubular, 5-lobed, sometimes bilabiate, pilose or glandular-hairy; tube campanulate or oblong, rarely dimidiate, somewhat inflated or lax, angular or ribbed; lobes unequal, usually longer than tube, valvate in bud. Corolla tubular, 5-lobed, somewhat bilabiate, various colours but if yellow, veins not dark; tube gently curved, usually narrow, globose at base and much enlarged, subcylindrical or funnel-shaped above, or ventricosely inflated; limb oblique or nearly regular, spreading or obliquely cup-shaped; lobes rounded or broadly obovate, entire or denticulate; upper 2 lobes interior in bud, sometimes connate higher up than others. Stamens 4, didynamous or +/- equal, included or scarcely exserted; filaments linear, arising about or below middle of corolla tube; anthers approximated in pairs, bithecate; thecae parallel or transverse, unequal, one fertile, acuminate, acute or mucronate at base, the other barren, longer and subulate-acuminate, or rarely subobsolete. Ovary bilocular, obovate, elliptic or ovate; placentation axile; ovules very many; style filiform, somewhat flattened, +/- as long as corolla tube, curved downwards near apex when ready for pollen; stigma thickened and various in shape. Fruit a globose, ovoid or conical, somewhat compressed, 2-grooved, loculicidal capsule. Seeds very many, small, irregularly oblong, truncate; testa reticulate, loose, membranous.