Erica

Erica is a genus of shrublets, shrubs and a few small trees, their family called Ericaceae. These perennial, evergreen plants, also called heaths, range from a few centimetres to around 7 m in height. Most heaths are single-stemmed reseeders after fire, although some coppice and resprout and a few can do both. The larger family includes azaleas and rhododendrons, as well as the fruits blueberries and cranberries.

Erica leaves mostly grow in whorls of four or five (occasionally six), rarely opposite or spiralling. The leaf-shape is mostly oblong, ovate or three-angled with margins rolled under, sometimes open-backed. The leaves are sometimes leathery, sometimes needle-like, while a few species have broad, flat and small blades, or the leaves are reduced and scale-like.

The flowers grow from leaf axils in whorls, racemes or umbel-like clusters at stem-tips or on small side-branchlets. Most flowers have pedicels, sometimes very short ones while few are stalkless. Bracts are always present, also bracteoles in some species. The calyces usually have four lobes or parts, variable in size and colour, growing from below the ovary. They sometimes exceed the corollas in size and may enlarge during fruiting.

The usually persistent corollas are mostly four-lobed and variously shaped. These include tubular, urn-shaped, globular, ovoid, flask-shaped, bell-shaped, cup-shaped or funnel-shaped ones, and although small also varying much in size. Some species have sticky corollas and some are hairy. Corolla colours are bright and varied where the pollinators are insects or birds, dull in wind-pollinated species.

The three to ten, mostly eight stamens in an Erica flower are free or fused, included or exserted. Some smaller flowered species have four stamens. The bilobed anthers are attached to their filaments at the back or the base, sometimes enhanced by appendages like crests and tails. The ripe anthers each opens via two pores to let the pollen out.

The ovaries are almost always superior, usually positioned on prominent discs. The number of locules or chambers per ovary is one to eight but mostly four and one to 180 ovules are present per locule. Sessile or stalked nectaries are usually prominent around the ovary base. The thread-like styles are included or exserted, rarely absent, the stigmas variously shaped, larger in wind-pollinated species.

The fruits are capsules that usually dehisce per locule or remain indehiscent, otherwise drupes or achenes. Old, dry flowers usually cover the fruits. The seeds are small, variable and smooth or spiky, often shaken out by wind that disperse them. In some species 50 000 seeds weigh less than one gram. 

This generic description is oversimplified, small groupings and individual species deviating variously in particular ways.

There are about 857 Erica species in Africa, Europe and Madagascar, 770 of which are found in southern Africa and a little under 700 of them in the Cape Floristic Region. These numbers still change slightly over time as discoveries are made in nature and taxonomies are corrected to accommodate new knowledge. Many Erica species form part of horticulture.

The plant in picture has not been identified. The small white corollas have small white sepals on top and short white pedicels from which they nod. The flowers grow in small clusters on numerous side-branchlets. The conspicuous brown anthers are exserted, the styles even further. The photo was taken on the Outeniqua Mountains (Manning and Helme, 2024; Leistner, (Ed.), 2000; Baker and Oliver, 1967; Wikipedia).