Plumbago.
In Family Plumbaginaceae there are 23 species commonly known as Plumbago or Leadwort.
Most are perennial herbs with some vines and rarely shrubs.
The usually branched stems are to 2 m or more in length.
They can be prostrate, climbing or trailing.
Stems are ribbed, hairless and have scattered glands that excrete calcium salts.
The alternately arranged leaves are in a spiral.
They have no petiole or a very short one and the base may clasp the stem.
The base may also have a lobe or auricle that clasps the stem.
Simple blades, up to 12 cm long are elliptic, oblanceolate to spatula-shaped.
The edges are smooth, the tip pointed or rounded and the base tapers.
The lower surface is often paler due to secretions from the chalk glands.
The edge may have hairs and the veins are pinnate.
The mostly terminal inflorescences are racemes or panicles.
Racemes are unbranched and flowers, on a pedicel open from the bottom first. Panicles are branched.
Some are branched only at the base with a spike-like raceme at the top.
The inflorescence midrib or axis may have glands or hairs.
The terminal branches or spikelets have one flower.
The short pedicels have a bract and 2 bracteoles (or described as 3 bracts) at the base.
The green bracts/bracteoles have chalk glands.
The 5-ribbed calyx has a tubular base with 5 teeth 2 mm long on the rim.
The tissue between the ribs is membranous.
Glandular hairs on the ribs secrete a sticky mucilaginous substance.
The corolla has a long narrow funnel-shaped base much longer than the calyx.
The 5 widely spreading lobes are round to obovate.
The pointed, rounded or flat tip has a mucro (short abrupt point).
Petals can be blue, purple, red, pink or white.
The 5 stamens extend to around the top of the corolla tube.
Free of the corolla, the bases of the filaments are dilated.
Linear anthers open through longitudinal slits.
The superior ovary is pear-shaped, ellipsoidal or ovoid.
From 5 fused carpels it has one locule.
The single style has 5 branches with linear stigmas on the inner surfaces.
Stigmas nay be held within or past the corolla tube.
Glands on the styles may or may not be on a stalk.
The membranous fruit are described as a capsule, utricle or achene.
They are surrounded by the calyx.
Fruit often open by splitting circumferentially near the base with the upper section breaking into 5 valves that may remain attached at the top.
The single black or dark brown seed is slightly flattened.
J.F.
