Appended '+' in Column Value

One column in a table has values for the attribute 'stream'. Some queries
return some rows where a stream name (only identified one so far) has an
appended '+'. I cannot update the table to remove that appended character,
and I've not seen this before.

Example:

2220 | STV | 2012-07-12 | Nematoda | | |
| | Omnivore | 50 | | StarvationCrk+| Owyhee
| | | | | |
| | | | | |
2701 | STV-10 | 2013-07-10 | Nematoda | | |
| | Omnivore | 36 | | StarvationCrk | Owyhee

I'd appreciate learning where that '+' originates and how to get rid of
it. A query to count the rows with the appendage returns zero:

select count(*) from benthos where stream = 'StarvationCrk';
count
-------
204

select count(*) from benthos where stream = 'StarvationCrk+';
count
-------
0

TIA,

Rich