5. Coldenia Linnaeus, Sp. Pl. 1: 125. 1753.
双柱紫草属 shuan zhu zi cao shu
Lobophyllum F. Mueller.
Herbs annual. Leaves alternate, margin lobed; secondary veins ending in sinuses. Inflorescences generally extra-axillary on leafy twigs or in forks of branches, sometimes glomerate. Flowers sessile or on short pedicels, 4-merous. Calyx 4-lobed. Corolla throat glabrous, naked or with 4 scaly appendages; lobes spreading, overlapping in bud. Ovary ovoid, somewhat 4-lobed, 2-loculed and with 2 ovules per locule, or falsely 4-loculed and with 1 ovule per locule; ovules anatropous. Styles 2, terminal, divided or united to middle; stigmas 2, usually divided. Fruit fleshy or dry, fastigiate or semiglobose, endocarp bony, divided into 4 1-seeded achenelike mericarps; mericarps ± united ventrally or joined to a central extension of receptacle. Seeds with little or no endosperm or not; embryo straight or curved.
For a discussion on the generic limits of Coldenia, see Richardson (Rhodora 79: 476. 1977).
One species: Cambodia, China, India, Indonesia, Malaysia, Pakistan, Sri Lanka, Thailand, Vietnam; Africa, Australia, North America, South America.