Their stems are variously but irregularly branched and in many species are
prostrate and creeping, rooting at
nodes. Such species are horticulturally useful components of flat
ground cover. The leaf placement or
phyllotaxis of the various species also varies, being either
opposite or
alternate, depending on the species. The leaves are fairly small and generally lightly to markedly
toothed. In shape the leaves are
simple, and those of various species vary from
elliptic, through
lanceolate, to short
linear. The flowers may be borne in terminal
racemes or
spikes, but most species bear numerous solitary flowers on
pedicels in leaf
axils. The pedicels generally twist in such a manner as to present the three-petalled lip uppermost, though in some species such as
Monopsis decipiens the two-petalled lip is usually on top. Consistency on this respect is most likely an
adaptation to favour preferred
pollinators, as it permits them to perform their functions most efficiently, both for the plant and for their own
reproductive success. Most species have flowers of either yellow or purple; the colours being vibrant and intense, much like those of many of the
Lobelia species. A few have flowers of various intermediate colours such as salmon. Flowers of some species, such as
Monopsis decipiens are colourfully patterned. Some species have white flowers. The
calyx has five lobes, its tube being fused to the
ovary. The
corolla has five petals, the corolla tube of most species being split nearly to its base, forming two lips or lobes. The upper lip has three of the petals, the lower lip the remaining two. In some species the petals of the two-part lip are nearly fully fused, but in others they are nearly completely split. There are five
stamens; in some species they are free from the tube of the corolla, but in others they grow from near the base of the tube. The
anthers, and in some species the upper parts of the filaments of the stamens, are joined into a ring around the
style. The tips of the anthers are bearded with little brushes of white hair. The ovary is
inferior and more or less fused to the calyx; it has two
locules, each containing many small
ovules. The style is thread-like, bent, and divides into slender, elongated flat
stigmas that are hairy at their bases and protrude from the ring of anthers. The seed capsule has two
valves and splits
loculicidally. ==Distribution==