Some plants are naturally rare because their habitat is rare. Others, however, are rare as a result of human activities. Annual investigations in unsurveyed areas locate rare plants not previously known to occur on the reservation or find new occurrences of known rare species. The Red data species list of South Africa changes over time.

26 indigenous species which belong to 4 families, of the plants housed at Johannesburg Botanical Garden Nursery are listed on the Red Data List of South Africa as rare, vulnerable, threatened or endangered.

Gasteria nitida var. armstrogiiThreats to endangered, vulnerable, threatened and rare species

The immediate causes of the worldwide decline of biological diversity are anthropogenic disturbance, habitat loss, and climate change. Introduced alien plants may outcompete some indigenous plants while favouring others; herbicides, fertilizers, pesticides and pollution from neighbouring fields may poison some plants, fertilize others and play havoc with insects which feed on plants or pollinate them.

Endangered, vulnerable, threatened and rare plants of Johannesburg Botanical Garden

Scientific Name Family National Status Method of propagation
Haworthia chlorocantha v. denticulifera Asphodelaceae Endangered Seeds
Haworthia serrata Asphodelaceae Critically Endangered Seeds
Haworthia limifolia Asphodelaceae Vulnerable Seeds
Haworthia retusa Asphodelaceae Vulnerable Seeds
Haworthia bryunsii Asphodelaceae Endangered Seeds
Lithops meyeri Aizoaceae Vulnerable Seeds
Lithops naureeniae Aizoaceae Vulnerable Seeds
Lithops oliviacea Aizoaceae Vulnerable Seeds
Lithops otzenzana Aizoaceae Vulnerable Seeds
Lithops leslie v. leslie Aizoaceae Near Threatened Seeds
Lithops helmutii Aizoaceae Vulnerable Seeds
Lithops dorothea Aizoaceae Endangered Seeds
Lithops divergens Aizoaceae Near Threatened Seeds
Lithops aucampiae ssp. euniceae Aizoaceae Vulnerable Seeds
Duvalia pillansii Apocynaceae Rare Seeds and cuttings
Duvalia elegens Apocynaceae Vulnerable Seeds and cuttings
Gasteria rowlinsonii Asphodelaceae Rare Seeds
Gasteria bicolor var. liliputana Asphodelaceae Rare Seeds
Gasteria ellaphaieae Asphodelaceae Rare Seeds
Gasteria nitida var. armstrogii Asphodelaceae Critically Endangered Seeds
Pelargonium appendiculatum Geraniaceae Endangered Seeds and cuttings
Aloe peglerae Asphodelaceae Endangered Seeds
Aloe buhrii Asphodelaceae Vulnerable Vulnerable
Aloe arenicola Asphodelaceae Near Threatened Seeds
Aloe dichotoma Asphodelaceae Vulnerable Seeds
Aloe ramosisima Asphodelaceae Endangered Seeds

Aloe dichotomaDefinitions of the Categories (according to IUCN)

Extinct: when the last remaining member of the species has died, or is presumed beyond reasonable.

Critically Endangered: when a species faces an extremely high risk of extinction in the immediate future.

Endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predationarmstro
Duvalia pillansii parameters.

Vulnerable: is when as species faces a high risk of extinction in the medium-term.

Near Threatened: may be considered threatened in the near future

Rare: when a species or an organism is very uncommon or scarce.