石龙尾属 shi long wei shu
Herbs, annual or perennial, in marshy areas or aquatic, often aromatic when bruised, with transparent dots. Stems erect, prostrate, or creeping, simple or much branched. Submerged leaves in aquatic species whorled, pinnately parted to capillary-multiparted, glabrous. Aerial leaves opposite to whorled, sessile or petiolate; leaf blade lanceolate or pinnately divided, glandular punctate, margin entire to serrate, if leaf undivided then veins pinnate or parallel. Flowers axillary and solitary or in axillary or terminal spikes or racemes, sessile or pedicellate. Bracteoles 2 or absent. Calyx tubular; lobes subequal or upper lobe larger than others. Corolla tubular or funnelform, 2-lipped; lower lip 3-lobed; upper lip entire or 2-lobed. Stamens 4, included, didynamous; anther locules stipitate. Ovary glabrous. Stigma 2-lamellate. Capsule included within calyx, septicidal. Seeds minute, numerous.
About 40 species: tropical to subtropical Africa, Asia, Australia, and Pacific Islands; ten species in China.
Plants with both submerged and aerial leaves.
Plants with aerial leaves only.
Aerial leaves undivided, 3-5-veined
4 Limnophila heterophylla
Aerial leaves divided, 1-3-veined.
Pedicel often as long as calyx or longer; bracteoles 1.5-3.5 mm; corolla 1-1.4 cm
3 Limnophila indica
Pedicel lacking or rarely to 1.5 mm; bracteoles absent or to 1.5 mm; corolla less than 1 cm.
Stems and calyx glandular hairy; calyx ca. 2 mm; corolla ca. 4 mm
2 Limnophila borealis
Stems and calyx eglandular hairy; calyx 4-6 mm; corolla 6-10 mm
1 Limnophila sessiliflora
Leaf veins parallel
5 Limnophila connata
Leaf veins pinnate or only midrib conspicuous.
Calyx smooth or with 5 raised veins in fruit; bracteoles lacking
6 Limnophila rugosa
Calyx with numerous raised veins in fruit; bracteoles present.
Fruiting pedicel recurved
10 Limnophila erecta
Fruiting pedicel not recurved.
Pedicel 5-20 mm
7 Limnophila aromatica
Pedicel 0.5-5 mm.
Pedicel 3-5 mm, villous to subglabrous; corolla 1-1.5 cm
8 Limnophila chinensis
Pedicel 0.5-3 mm, hispidulous; corolla 0.5-1 cm
9 Limnophila repens