dumping ground

noun3

1. •
   A landfill.
2. •
   Any place where unwanted items are sent.

   • Around 25 years ago, it was used as a dumping ground for Toton locomotives destined for scrapyards. — 2021
3. •
   A presumably polyphyletic supraspecific taxon where species of unclear affinities are placed.

   • Several genera, e.g. Miltonia Lindl., Odontoglossum Kunth and Oncidium Sw., have historically been viewed as taxa of convenience and thus became dumping grounds for species of unclear relationships. — 2008