Refactor the unstructured text into a valid JSON dictionary. The key names follow the Darwin Core Archive Standard. If a key lacks content, then insert an empty string. Fill in the following JSON structure as required: {"catalogNumber": "", "order": "", "family": "", "scientificName": "", "scientificNameAuthorship": "", "genus": "", "subgenus": "", "specificEpithet": "", "verbatimTaxonRank": "", "infraspecificEpithet": "", "identifiedBy": "", "recordedBy": "", "recordNumber": "", "verbatimEventDate": "", "habitat": "", "occurrenceRemarks": "", "associatedTaxa": "", "country": "", "stateProvince": "", "county": "", "municipality": "", "locality": "", "decimalLatitude": "", "decimalLongitude": "", "verbatimCoordinates": "", "minimumElevationInMeters": "", "maximumElevationInMeters": ""}
1993-05-20 5c   8524 C    [B/ CAREX NIGROMARGINATA   buchanan m4oL  Thomas F. Wieboldt /       e_Yo2 1380597   x` UNITED StTATES  8 cyperaceae    < r VIRGINI  .myGR nigromarginata      
{"catalogNumber": "1380597", "order": "", "family": "Cyperaceae", "scientificName": "Carex nigromarginata", "scientificNameAuthorship": "", "genus": "", "subgenus": "", "specificEpithet": "nigromarginata", "verbatimTaxonRank": "", "infraspecificEpithet": "", "identifiedBy": "", "recordedBy": "Thomas F. Wieboldt", "recordNumber": "8524", "verbatimEventDate": "1993-05-20", "habitat": "", "occurrenceRemarks": "", "associatedTaxa": "", "country": "United States", "stateProvince": "Virginia", "county": "Buchanan", "municipality": "", "locality": "", "decimalLatitude": "", "decimalLongitude": "", "verbatimCoordinates": "", "minimumElevationInMeters": "", "maximumElevationInMeters": ""}