Common Ground Sugarbush

Scientific Name
Protea acaulos (L.) Reichard
Higher Classification
Protea acaulis Thunb., Protea glaucophylla Salisb.
Common Names
Aardroos (a), Common Ground Sugarbush (e), Ground Protea (e)
National Status
Status and Criteria
Near Threatened A2c
Assessment Date
A.G. Rebelo, H. Mtshali & L. von Staden
Protea acaulos is a widespread species, but has declined significantly across the Cape Lowlands, and continues to decline due to ongoing habitat loss and degradation. A population reduction of 23-28% over three generations is inferred from habitat loss over the past 150-300 years. It therefore nearly meets the thresholds for Vulnerable under criterion A2.
South African endemic
Provincial distribution
Western Cape
This species is widespread in the Western Cape, where it occurs from the Cederberg to the Cape Peninsula, and eastwards along the coastal mountains to Bredasdorp. It also occurs in the Riviersonderend Mountains and an isolated subpopulation is known from the Langeberg Mountains near Barrydale.
Habitat and Ecology
Major system
Major habitats
Breede Sand Fynbos, Breede Alluvium Fynbos, Cape Winelands Shale Fynbos, Breede Shale Fynbos, Peninsula Shale Fynbos, Peninsula Granite Fynbos, Greyton Shale Fynbos, Elim Ferricrete Fynbos, Swartruggens Quartzite Fynbos, Agulhas Sand Fynbos, Hangklip Sand Fynbos, Cape Flats Sand Fynbos, Atlantis Sand Fynbos, Leipoldtville Sand Fynbos, Swartland Alluvium Fynbos, Boland Granite Fynbos, North Langeberg Sandstone Fynbos, Peninsula Sandstone Fynbos, South Hex Sandstone Fynbos, Piketberg Sandstone Fynbos, Winterhoek Sandstone Fynbos, Cederberg Sandstone Fynbos, Elgin Shale Fynbos, Graafwater Sandstone Fynbos, Swartland Granite Renosterveld, South Sonderend Sandstone Fynbos, North Sonderend Sandstone Fynbos, Overberg Sandstone Fynbos, Kogelberg Sandstone Fynbos, Hawequas Sandstone Fynbos, Breede Quartzite Fynbos, Olifants Sandstone Fynbos
It prefers sandy and alluvial soils on flats and lower slopes in montane and lowland fynbos, but is also encountered in shale and granite fynbos, from sea level to 1800 m. It is a long-lived species, and survives fires by resprouting from underground stems. Wind-dispersed seeds are stored in fire-resistant inflorescences, and released after fires. It is pollinated by rodents.
About 26% of this species' habitat is already irreversibly modified, and loss continues. The main causes of habitat loss are urban and agricultural expansion, as well as historical loss to commercial timber plantations on the lower slopes of mountains across most of its range. It is also severely threatened by competition from dense infestations of alien invasive plants on the southern slopes of the Riviersonderend Mountains, the Agulhas Plain, the Caledon Swartberg, and in sand fynbos between Malmesbury and Mamre. In small lowland remnants, it is subjected to inappropriate fire management, particularly fire exclusion, which leads to reduced recruitment, as this species is dependent on fires to stimulate seed release and germination. Many lowland fragments are also overstocked with livestock, leading to the spread of alien invasive grasses as well as general degradation of the vegetation.

It occurs in low densities and solitary plants are often encountered. It has declined significantly in the Cape Lowlands, and a population reduction of 23-28% is inferred from habitat loss over the past three generations. If recent rates of habitat loss is projected into the future, population reduction could possibly exceed 30% within three generations, as this is a very long-lived species. Most of its remaining habitat is however in montane areas where the rate of loss is significantly lower than in the lowlands, and projected population reduction is very uncertain.

Population trend
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Protea acaulos (L.) ReichardNT A2c2020.1
Protea acaulos (L.) ReichardLeast Concern Raimondo et al. (2009)

Goldblatt, P. and Manning, J.C. 2000. Cape Plants: A conspectus of the Cape Flora of South Africa. Strelitzia 9. National Botanical Institute, Cape Town.

Raimondo, D., von Staden, L., Foden, W., Victor, J.E., Helme, N.A., Turner, R.C., Kamundi, D.A. and Manyama, P.A. 2009. Red List of South African Plants. Strelitzia 25. South African National Biodiversity Institute, Pretoria.

Rebelo, T. 2001. Sasol Proteas: A field guide to the proteas of southern Africa. (2nd ed.). Fernwood Press, Vlaeberg, Cape Town.

Rebelo, A.G., Mtshali, H. & von Staden, L. 2019. Protea acaulos (L.) Reichard. National Assessment: Red List of South African Plants version . Accessed on 2024/05/28

Comment on this assessment Comment on this assessment
Distribution map

© C. Merry

© C. Merry

© C. Merry

Search for images of Protea acaulos on iNaturalist