[Taxacom] Authority with date (zoo) / without date (bot)

[rch]

In the European Commission's «draft initial list of invasive alien
species of Union concern»
https://members.wto.org/crnattachments/2015/SPS/EEC/15_2887_00_e.pdf
the invasive alien species of animal are listed with authority plus date:-
    Callosciurus erythraeus Pallas, 1779,
    Corvus splendens Viellot, 1817,
    Eriocheir sinensis H. Milne Edwards, 1854,
    ...

and the invasive alien species of plant with authority minus date:-
    Baccharis halimifolia L,
    Cabomba caroliniana Gray,
    Eichhornia crassipes (Martius) Solms,
    ...

Is this zoo/bot difference usual taxonomic practice, or is there some
other explanation?

Richard H