as per request.

Calling all Gauteng iNatters to assist in searching for these 4 plant species across the province:

APOCYNACEAE Ceropegia discoideum (CRPE)
(was Brachystelma discoideum)
This species is possibly extinct at the type locality (Shoshanguve, north of Pretoria) where it has not been seen since 1968, despite many repeated searches. There are some indications that it possibly has a wider distribution in similar sandy bushveld habitat in North West and Mpumalanga provinces, but there has been no other collections or confirmed records. It is possibly extinct, but more field surveys in suitable habitat is needed.
(full red list account)
Ralf Peckover describes the flower colour variation here:
http://www.flora-africa.com/Flower%20colour%20variation%20in%20Brachystelma%20discoideum.pdf

APOCYNACEAE Miraglossum laeve (CRPE)
A rare and very poorly known species, last collected in 1960. Dedicated searches on the hills south of Pretoria and the Vredefort Dome north-east of Parys have thus far failed to relocate it and is possibly already extinct due to habitat loss and degradation.
(full red list account)

ASTERACEAE Macledium pretoriense Pretoria Karmedik (EX)
(was Dicoma pretoriense)
The only known locality for this species - hillsides in Pretoria - has been transformed by urban development. It was last collected in 1925.
(full red list account)

ORCHIDACEAE Holothrix micrantha Egoli Hair Orchid (CRPE)
A rare, range-restricted species last recorded in 1925. Several searches within its habitat - Gold Reef Mountain Bushveld, Egoli Granite Grassland - have thus far failed to relocate this species in the wild. It is possibly extinct, but also cryptic and easily overlooked, and a small chance remains that it may still be relocated.
(full red list account)

iNatters across KZN are required to search for these plant species, currently listed as Critically Endangered, Possibly Extinct (CRPE):

APOCYNACEAE Ceropegia rudatisii Hillcrest Lanternflower
Known from a few collections in an area extensively transformed by agriculture, forestry, and invasive alien plants. Searches across KwaZulu-Natal Sandstone Sourveld vegetation revealed very little pristine vegetation remains within the known range of this species and no subpopulations were found.
(full red list account)

APOCYNACEAE Pachycarpus rostratus Nkandla Pachycarpus
Known from a single record from an unspecified site in the Nkandla district. This area is extensively transformed and degraded as a result of overgrazing by livestock, a deleterious fire regime, afforestation and crop cultivation. It has not been seen in more than 100 years.
(full red list account)

APOCYNACEAE Riocreuxia woodii Inanda Candlevine
Known from an inexact type locality at Inanda near Durban, where it was collected in 1884. Searches have been unsuccessful, however, experts believe that it may still be relocated as intact habitat remains in the area.
(full red list account)

ERICACEAE Erica natalensis Mont-Aux-Sources Heath
Only known from the type collection, which came from Mont-Aux-Sources in the KwaZulu-Natal Drakensberg. The area where it is thought to have been collected is degraded due to livestock overgrazing. Search efforts are ongoing, but have not been successful to date.
(full red list account)

FABACEAE Lotononis dichiloides Fernham Lotononis
This species was last collected in the 1930s. Its habitat, KwaZulu-Natal Coastal Belt Grassland, is >90% transformed due to urban expansion, and agriculture and is degraded due to overgrazing and too frequent fire.
(full red list account)

MELIACEAE Turraea streyi Daintyleaf Honeysucklebush)
Two known wild sub-populations disappeared as a result of dense invasive alien encroachment, and one introduced sub-population of three individuals remains near the type locality. More than 80% of its coastal habitat has been transformed due to sugarcane cultivation, coastal development, and alien plant invasion. There is little hope that it could be found elsewhere in the former range.
(full red list account)

PASSIFLORACEAE Adenia natalensis Natal Elephantroot
Known from two collections made in 1865, this presumably very rare species may still be relocated in the area where it is thought to have been collected as intact habitat still remains. Search efforts are ongoing, but have not been successful to date.
(full red list account)