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": ""}
  B: 1886       R MUHLENBERGIA  cg Poales  NmF Muhlenbergia mexicana     #R $t Davidson      NP (l.) trin.   ?>B( UNITED STATES  s.n.  S^  1417765 ^w    NASHVILLE h5B  
{"catalogNumber": "1417765", "order": "Poales", "family": "", "scientificName": "Muhlenbergia mexicana", "scientificNameAuthorship": "(L.) Trin.", "genus": "Muhlenbergia", "subgenus": "", "specificEpithet": "", "verbatimTaxonRank": "", "infraspecificEpithet": "", "identifiedBy": "", "recordedBy": "", "recordNumber": "s.n.", "verbatimEventDate": "1886", "habitat": "", "occurrenceRemarks": "", "associatedTaxa": "", "country": "United States", "stateProvince": "", "county": "Davidson", "municipality": "", "locality": "Nashville", "decimalLatitude": "", "decimalLongitude": "", "verbatimCoordinates": "", "minimumElevationInMeters": "", "maximumElevationInMeters": ""}