Plumbaginaceae are perennial herbs or shrubs. Leaves are simple, alternate, stipulate or exstipulate. Inflorescence various, racemes, spikes, panicles, cymose heads or dichasial cymes, etc. Flowers are bisexual, actinomorphic or slightly zygomorphic, hypogynous and pentamerous.
Calyx tubular, 5-lobed, membranous, persistent, lobes valvate. Corolla tubular; lobes 5, often free very near to the base, contorted. Stamens 5, opposite to petals and often epipetalous; anthers bilocular, introrse, dehiscing longitudinally.
Ovary of 5 carpels, syncarpous, superior, unilocular with a single basal ovule; funiculars long; styles 5, free or connate at the base; stigmas simple. Fruit a utricle or a capsule dehiscing transversely, enclosed by persisting membranous calyx; pericarp thin. Seed cylindrical with a straight embryo usually surrounded by mealy or fleshy endosperm; rarely endosperm absent.
A few species of Plumbago are scandent or climbing, e.g. P. scandens Linn. P. auriculata Bl., P. rosea Linn, and P. caponsis Thunb. Acantholimon species are dwarf with short tufted stem and branches forming a cushion. In this genus as well as in Armeria the leaves are very narrow and linear and often needle-like.
In Armeria the cymes are clustered in dense heads, the bracts surrounding the peduncle unite at base forming a tubular sheath, the calyx is often spurred rendering the flower zygomorphic. The upper portion of the corolla is deciduous while the tubular lower portion is usually persistent. Pollens are trinucleate.
The family consists of about 300 species under 10 genera growing mostly in semi- arid regions, salt-steppes and the sea coasts of the Old- as well as the New-World. A few are alpine and some grow in the artic region.
Aegialitis is a halophytic genus, A. rotundifolia Roxb being found in the Sunder ban forests of W. Bengal and Bangladesh and the coastal forest of Andaman. Plumbago zeylanica Linn, is quite common in some parts of India in the plains. Plumbaginaceae comes close to Primulaceae and also to the families included in Centrospermae (or Caryophyllales). It is also considered to be related to Polygonaceae to some extent.
The family is divided into 2 tribes as given below:
I. Plumbagineae:
Inflorescence simple; styles connate to a greater extent.
II. Staticeae:
Inflorescence compound; styles free up to the base. The family is splatted up by some workers into 3 smaller families, viz. Limoniaceae, Aegialitidaceae and Plumbaginaceae. Plumbaginaceae is not much important economically.
A few species of Pumbago is poisonous and have medicinal properties also. P. indica Linn. (Syn. P. rosea Linn.) has antiseptic properties and is useful in early cases of leucoderma and baldness. P. zeylanica Linn, has the same properties and is also used to raise blisters.