Taxonomy
Scientific Name
Pterygodium microglossum (Lindl.) Schltr.
Higher Classification
Monocotyledons
Family
ORCHIDACEAE
Synonyms
Corycium microglossum Lindl.
National Status
Status and Criteria
Endangered C2a(i); D
Assessment Date
2022/04/07
Assessor(s)
L. von Staden & W.R. Liltved
Justification
This species used to occur on the Cape Flats and in Upper Breede River Valley, it is now extinct in these areas due to urban expansion and crop cultivation. Sixty percent of known subpopulations have been lost, and only three remain. All subpopulations are small, having less than 70 individuals. This species is threatened by invasive alien plants and lack of reproduction as its pollinator has disappeared from the remaining habitat fragments where it occurs. It is therefore assessed as Endangered under criteria C and D.
Distribution
Endemism
South African endemic
Provincial distribution
Northern Cape, Western Cape
Range
This species occurs from Nieuwoudtville to the Cape Peninsula and has gone extinct on the Cape Flats.
Habitat and Ecology
Major system
Terrestrial
Major habitats
Swartland Granite Renosterveld, Peninsula Sandstone Fynbos, Bokkeveld Sandstone Fynbos, Atlantis Sand Fynbos, Breede Alluvium Fynbos
Description
Plants grow on sandy soils, on the edges of seasonally wet pans or watercourses on low mountain slopes and flats below 600 m.
Threats
This species secretes non-volatile oil as a pollinator reward. Despite observations of the small population at Riverlands and Kommetjie, no pollinators were observed and all flowers remained unpollinated. As only one oil-collecting bee is known to be active at the time of year P. microglossum flowers, it is probably pollinated by Rediviva gigas. It is possible R. gigas no longer exists at these sites and that plants are surviving solely through vegetative reproduction. Habitat degradation through invasive species is another threat to this species: Riverlands is surrounded by degraded vegetation severely infested by invasive Acacias. Although the Acacias have been cleared inside the Riverlands reserve, they remain a potential threat. Aliens are a severe threat to the plants at the base of the Rooiberg on the Cape Peninsula Urban expansion and agriculture caused probably about 60% decline in the number of subpopulations of this species in the past, but the exact timing of the loss of subpopulations/locations are not known for certain. Loss to agriculture is still a potential threat to plants at Romansrivier.
Population

It is currently recorded to be extant at only three subpopulations, the largest has 60 plants, the second has 37 plants and the third only one plant.


Population trend
Decreasing
Conservation
It is conserved in Riverlands Nature Reserve.
Assessment History
Taxon assessed
Status and Criteria
Citation/Red List version
Pterygodium microglossum (Lindl.) Schltr.EN C2a(i); D2014.1
Corycium microglossum Lindl.CR A3c; B1ab(iv,v)+2ab(iv,v); C2a(i,ii); DRaimondo et al. (2009)
Corycium microglossum Lindl.EN A1cVictor (2002)
Corycium microglossum Lindl.Endangered Hilton-Taylor (1996)
Bibliography

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.


Hilton-Taylor, C. 1996. Red data list of southern African plants. Strelitzia 4. South African National Botanical Institute, Pretoria.


Liltved, W.R. and Johnson, S.D. Unpublished. The Cape Orchids - Wild orchids of the Cape Floral Kingdom.


Linder, H.P. and Kurzweil, H. 1999. Orchids of southern Africa. A.A. Balkema, Rotterdam.


Manning, J.C. and Goldblatt, P. 2012. Plants of the Greater Cape Floristic Region 1: The Core Cape Flora. Strelitzia 29. South African National Biodiversity Institute, Pretoria.


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.


Victor, J.E. 2002. South Africa. In: J.S. Golding (ed), Southern African plant Red Data Lists. Southern African Botanical Diversity Network Report 14 (pp. 93-120), SABONET, Pretoria.


Citation
von Staden, L. & Liltved, W.R. 2022. Pterygodium microglossum (Lindl.) Schltr. National Assessment: Red List of South African Plants version . Accessed on 2024/06/17

Comment on this assessment Comment on this assessment
Distribution map

© W.R. Liltved


Search for images of Pterygodium microglossum on iNaturalist