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Louisiana Flora checklist with synonyms and excluded taxa
(MS Excel Document, download it here!) Updated July 2004

Checklist without synonyms, etc.
(MS Excel Document) Updated July 2004

Explanation of Scores given in the Checklist


This is a list of currently accepted taxa, some (not all) synonyms, and some excluded taxa for vascular plants in Louisiana, including native, introduced, and some (not all) cultivated plants. To repeat, NOT ALL BI- OR TRINOMIALS ON THE FIRST, COMPLETE LIST ARE ACCEPTED FOR THE STATE. Please read the scores carefully before using the data provided in this list.

Materials and Methods and Motivation

The following were used as sources for names for the checklist:

The LSU vascular plant database (

Thomas and Allen's checklists for Louisiana, including their excluded taxa and synonyms

The USDA's NRCS Plants Database ( advanced query for Louisiana

Published volumes of Flora of North America (FNA): 2-4, 22-23, 25-26

Since not all sources agree on taxonomy, a standard had to be chosen. Flora of North America, when available, was chosen as the most up-to-date and hence the standard for taxonomic accuracy. All other sources were brought up to that standard as best as possible. When FNA was not available, the USDA website was considered the standard, and other sources were adjusted accordingly for comparative purposes. Bi- and trinomials not found in these published works were checked in Index Kewensis or Gray Card Index.

Volume 25 of FNA, Poaceae Part 2, presented unique problems. Unlike the other FNA volumes, distributional data by state is not given for subspecies and varieties. Species-level maps are difficult at best to interpret (printed state-by-state lists not published). Therefore, unless it is explicit in the descriptions, the presence/absence of infraspecific grass taxa based on FNA is treated as missing data, as if FNA were not published. This was also true of several hybrid taxa, especially in Quercus. Hybrids were mentioned under species descriptions, but distributions were not provided. These cases were also treated as missing data for FNA.

The following simple scoring system (table below) was developed for each taxon, representing the degree of agreement as to whether a particular taxon can be found within Louisiana between each literature source and at the LSU Herbarium. This is not a grand proclaimation of right vs. wrong, but a simple literature review and a "state of the state". The motivation to develop this list came primarily from two places (1) when I began a statewide treatment of Cyperus in 2003, I noted huge discrepancies amongst authorities as to which species occurred in Louisiana, and (2) when I needed to know the total number of taxa in Louisiana, and I needed a list of them for a grant proposal, I again noted great discrepancies between published lists and the USDA website. Whether these discrepancies are all taxonomic artifacts are still up for debate. Keep in mind this is a simple presence/absence list: endemism, cultivation, etc. were not considered under the current scoring system as this list is very preliminary. More detailed study is warranted given the apparent disagreement amongst the three floras (see below). Nativity information was recorded and will be incorporated in future versions of the checklist.

The take-home message is that if a taxon has a score of "1" or "A", everyone agrees it is in Louisiana and that's great. Some other number or letter indicates some other potential problem or conflict that may need some resolution at some point.

Score Explantation
1 Accepted by FNA, Thomas & Allen, and USDA
2 Accepted by FNA, USDA, missing/excluded/synonymized by Thomas & Allen
3 Accepted by FNA, missing/excluded/synonymized by USDA and Thomas & Allen
4 Accepted by FNA, Thomas & Allen, missing/excluded/synonymized by USDA
5 Excluded or out of state by FNA, accepted by USDA and Thomas and Allen
6 Excluded or out of state by FNA and USDA, accepted by Thomas and Allen
7 Excluded, missing or out of state by FNA and Thomas and Allen, accepted by USDA
8 Excluded, missing, or synonymized by FNA, USDA, and Thomas & Allen, but LSU may have specimens
A Accepted by the USDA and Thomas and Allen (no FNA information)
B Accepted by the USDA, missing or synonymized in Thomas and Allen (no FNA information)
C Accepted by Thomas and Allen, not found in USDA (no FNA information)
D Not in either Thomas and Allen or USDA, missing/excluded/synonymized/out of state (no FNA information), but LSU may have specimens
H Hybrid taxon, not recognized formally, or an intermediate
S Taxon synonymized by FNA, although accepted by USDA and/or Thomas & Allen at some point
T Basionym from the type collection at LSU