Here's a 
sample screen shot,
and
here's the readme
file that goes with it.
The colors are a bit cartoonish compared to the actual plants, granted. All I wanted was to get a handle on the way this complicated group of plants changed through the seasons.
If you're interested in downloading the complete database, email me. You need Microsoft Excel to be able to do anything with it.
"It's a most excellent spreadsheet."
-Josh Gordon, Chief Programmer at eBay
"Art, don't be shy, how do you really feel about these plants, Art, do
you like them or not?"
-Mike McGrath, Host of "You Bet Your Garden" on WHYY radio.
The Heather Society is an an excellent source of information, and they have a searchable version of their Handy Guide to Heathers online. The paper version of the book is well worth having, too.