Pretty Confusing Ericas

There are many pretty species of Erica but only one truly bears the name: Erica pulchella. (“Pulchella” is the Latin diminutive for beautiful, i.e. pretty.) It forms low branched shrubs with numerous dense spikes of small purplish red urn-shaped flowers. It grows from the Cape Peninsula to Kogelberg, and along the coast towards Mossel Bay. However, in the Klein River Mountains and low hills towards Elim plants that look remarkably similar to Erica pulchella are usually known as a different species: Erica longiaristata. The two species are frequently confused and some botanists therefore think that they should be regarded as the same species.

Erica pulchella (Ericaceae)
Spike of Erica pulchella
Erica longiaristata and Erica pulchella (Ericaceae)
Comparison of Erica longiaristata and Erica pulchella. Note the erect new flowers of Erica longiaristata, but slightly pendent ones of Erica pulchella
Erica longiaristata and Erica pulchella flowers (Ericaceae)
Erica longiaristata and Erica pulchella flowers. The latter the tube is “pinched” just before the lobes. The bracteoles are also visible on the pedicels of Erica pulchella
Erica longiaristata aristate stamens and style (Ericaceae)
The stamens of both species have long tails to the anthers that run down the filament.

Erica longiaristata is named on account of the anthers, which have long tails (aristate). These are joined to the filament of the stamen for much of their length. However, Erica pulchella also have these long-tailed anthers joined to the filament, so this character is not diagnostic. The original descriptions of Erica longiaristata notes the similarity to Erica pulchella but highlights the difference in the shape of the flower. In particular, that the tube of the flower is not inflated and that the lobes flare outwards from the mouth. This character is indeed noticeable in specimens from the Klein River Mountains, where the short tube of the flower merges straight into the spreading lobes. In plants of Erica pulchella, there is usually a small constriction in the tube just before the lobes.

Erica longiaristata and Erica pulchella flowers in cross-section (Ericaceae)
Erica longiaristata and Erica pulchella flowers in cross-section

On its own, this difference is very slight and it would be doubtful whether the two species should be maintained as distinct. However, a comparison between a plant from the Kogelberg and one from Phillipskop shows other characters that could prove to be helpful. In the plant of Erica pulchella the flowers as they open often have strongly curved pedicels, so that they hang downwards. In contrast, the plant of Erica longiaristata has its pedicels held upright as the flower opens, and though they do turn outwards, they never hang downwards. Another difference with the pedicels is the position of the bracts and bracteoles. These tiny small leaves are all clustered at the base in the specimen of Erica longiaristata but only the bract is at the base in the Erica pulchella, the two bracteoles can found up to halfway up the pedicel. Other differences can be seen inside the flower. The ovary is minutely hairy in the Kogelberg Erica pulchella but glabrous in Phillipskop Erica longiaristata. The style is also very short in Erica pulchella, not reaching the sinuses of the lobes, but extends beyond the sinuses in Erica longiaristata and is easily visible in the mouth of the flower.

Erica longiaristata (Ericaceae)
Plant of Erica longiaristata

Together these differences make a convincing argument for keeping the two species separate. Unfortunately, this is not the whole story as it is based on just two samples. The challenge is knowing how consistent these differences are and whether they correlate with one another and the ecology, distribution and habitats of the plants in question. That will only be known after a much longer study of more plants but this will hopefully give keen botanists a start to examine more carefully whether the plant they have seen is Erica longiaristata or Erica pulchella. Fortunately, to the layman the differences are insignificant and both species are beautiful plants of midsummer along the southern Cape coast.

Erica longiaristata

  • Flowers pink
  • New flowers ± erect to spreading
  • Corolla tube more or less parallel before spreading lobes
  • Bracts and bracteoles hidden at the base of the pedicel
  • Style long, beyond the sinuses of the lobes, easily visible in mouth of flower
  • Ovary glabrous
  • Klein River Mountains to Bredasdorp and Elim

Erica pulchella

  • Flowers deep pink to purplish
  • New flowers spreading to pendent
  • Corolla tube slightly inflated then pinched before spreading lobes
  • Bracts at base, two bracteoles up to halfway up the pedicel
  • Style short, not reaching the sinuses of the lobes and rather hidden within the flower
  • Ovary shortly hairy or possibly glabrous
  • Cape Peninsula to Mossel Bay

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