13. Ruellia Linnaeus, Sp. Pl. 2: 634. 1753.
芦莉草属 lu li cao shu
Authors: Jia-qi Hu & Thomas F. Daniel
Blechum P. Browne; Cryphiacanthus Nees; Dipteracanthus Nees.
Herbs [or shrubs], perennial, prostrate to erect, with cystoliths. Leaves sessile or petiolate; leaf blade margin entire, crenulate, or dentate. Inflorescences axillary or terminal, reduced or expanded dichasia, sometimes forming dichasiate spikes, thyrses, or panicles, sometimes reduced to a solitary flower; bracts opposite, usually green, margin entire; bracteoles 2 [or absent]. Flowers [sessile or] subsessile to pedicellate. Calyx deeply 5-lobed; lobes equal or subequal. Corolla funnel-shaped; tube basally with a narrowly cylindric portion, usually expanded apically into a distinct throat; limb 5-lobed; lobes usually ovate to orbicular, equal to unequal in size, contorted in bud. Stamens 4, didynamous, usually included in corolla tube; filaments sometimes connate in pairs at base; anthers 2-thecous; thecae equal, parallel to subsagittate, muticous at base; staminode 1 or absent. Ovary with up to 10 ovules per locule; style usually included in corolla tube or slightly exserted; stigma 2-lobed, lobes equal or unequal. Capsule stipitate or not stipitate, [4-]12-26-seeded; retinacula present; septa with attached retinacula remaining attached (or separating in Ruellia blechum) to inner wall of mature capsule. Seeds discoid, usually pubescent with hygroscopic trichomes.
About 250 species: tropical to temperate regions worldwide; four species (one endemic, two introduced) in China.
Blechum and Dipteracanthus are included in Ruellia based on morphological and molecular data (C. Ezcurra, Ann. Missouri Bot. Gard. 80: 787-845. 1993; E. Tripp, Syst. Bot. 32: 628-649. 2007; E. Tripp et al., Taxon 58: 893-906. 2009).