How do you filter records based on Observation fields - for instance host plant?

[pisum]

see:

• https://forum.inaturalist.org/t/getting-ids-for-dna-barcoded-observations/26657/5
• https://forum.inaturalist.org/t/how-to-use-inaturalists-search-urls-wiki-part-2/18792#heading--obs--field