Belgium
A
grass unique to
Belgium, the Brome of the Ardennes Bromus
bromoideus (Wikipedia),
has recently been reintroduced 85 years after becoming extinct in the
wild after the successful germination of seeds stored in botanical
gardens (p. 14 of Kew pdf).
Endemic vascular plant microspecies include the buttercups Ranunculus pachyphyton (GBIF) and Ranunculus brabantianus (GBIF) and a bramble Rubus orthocladoides (GBIF).
Among the invertebrate species described from Belgium and not known
from elsewhere are a cave-dwelling rove beetle Tychobythinus belgicus
(p. 4 of CWEPSS
pdf), a dance fly Drapetis bruscellensis (ResearchGate), a parasitic wasp Cleruchus
raignieri (fig. 37 on p. 55 of RBINS pdf), the cave-dwelling springtails Oncopodura
dethieri
(ResearchGate)
and Deharvengiurus
severini (fr.wikipedia)
(BHL),
a sheetweb spider Diplocephalus
caecus (araneae) (p. 47 of RBINS pdf),
a cave-dwelling mite Veigaia
hubarti (PLAZI), and a bryozoan Escharella gilsoni (p. 10 of RBINS pdf).
Two freshwater diatoms, Eunotia belgica and Encyonopsis horticola, have been described from Belgium (JSTOR).
Fungi known only from Belgium include a webcap Cortinarius vandervekenianus (fig. 4 at KVMV pdf).
An overview of the cave-dwelling fauna of Belgium is at (Michel Dethier WM pdf).